Removed underscore_to_camelcase

No need to bother both developers (that need to create class names compatible 
with file name, which is not obvious if not looking into main Powerline class) 
and computer (that needs to recompute class name each time) if it is possible to 
bother only developers (or only computer, but this contributes to higher startup 
times).

About not obvious: when you look into zsh_prompt.py and see only 
ZshPromptRenderer name you only think that powerline upstream is following 
strict code style. You don’t think there is a technical reason for such naming, 
like you don’t think there is technical reason for having blank lines. When you 
look into zsh_prompt.py and see `renderer = ZshPromptRenderer` it is obvious 
that there is technical reason for writing code this way because new variable is 
never used in the module itself.

powerline/__init__.py

@@ -6,19 +6,18 @@ import os
 import sys
 
 from powerline.colorscheme import Colorscheme
-from powerline.lib import underscore_to_camelcase
 
 
 def open_file(path):
 	return open(path, 'r')
 
 
-def load_json_config(search_paths, config_file, load=json.load, open=open_file):
+def load_json_config(search_paths, config_file, load=json.load, open_file=open_file):
 	config_file += '.json'
 	for path in search_paths:
 		config_file_path = os.path.join(path, config_file)
 		if os.path.isfile(config_file_path):
-			with open(config_file_path) as config_file_fp:
+			with open_file(config_file_path) as config_file_fp:
 				return load(config_file_fp)
 	raise IOError('Config file not found in search path: {0}'.format(config_file))
 
@@ -65,9 +64,8 @@ class Powerline(object):
 		# Load and initialize extension renderer
 		renderer_module_name = renderer_module or ext
 		renderer_module_import = 'powerline.renderers.{0}'.format(renderer_module_name)
-		renderer_class_name = '{0}Renderer'.format(underscore_to_camelcase(renderer_module_name))
 		try:
-			Renderer = getattr(__import__(renderer_module_import, fromlist=[renderer_class_name]), renderer_class_name)
+			Renderer = __import__(renderer_module_import, fromlist=['renderer']).renderer
 		except ImportError as e:
 			sys.stderr.write('Error while importing renderer module: {0}\n'.format(e))
 			sys.exit(1)

powerline/lib/__init__.py

@@ -7,11 +7,6 @@ from powerline.lib.humanize_bytes import humanize_bytes  # NOQA
 from powerline.lib.url import urllib_read, urllib_urlencode  # NOQA
 
 
-def underscore_to_camelcase(string):
-	'''Return a underscore_separated_string as CamelCase.'''
-	return ''.join(word.capitalize() or '_' for word in string.split('_'))
-
-
 def mergedicts(d1, d2):
 	'''Recursively merge two dictionaries. First dictionary is modified in-place.
 	'''

powerline/renderers/bash_prompt.py

@@ -11,3 +11,6 @@ class BashPromptRenderer(ShellRenderer):
 	@staticmethod
 	def escape(string):
 		return string.replace('\\', '\\\\').replace('$', '\\$').replace('`', '\\`')
+
+
+renderer = BashPromptRenderer

powerline/renderers/ipython.py

@@ -7,3 +7,6 @@ class IpythonRenderer(ShellRenderer):
 	'''Powerline ipython segment renderer.'''
 	escape_hl_start = '\x01'
 	escape_hl_end = '\x02'
+
+
+renderer = IpythonRenderer

powerline/renderers/pango_markup.py

@@ -29,3 +29,6 @@ class PangoMarkupRenderer(Renderer):
 			if attr & ATTR_UNDERLINE:
 				awesome_attr += ['underline="single"']
 		return '<span ' + ' '.join(awesome_attr) + '>' + contents + '</span>'
+
+
+renderer = PangoMarkupRenderer

powerline/renderers/shell.py

@@ -65,3 +65,6 @@ class ShellRenderer(Renderer):
 	@staticmethod
 	def escape(string):
 		return string.replace('\\', '\\\\')
+
+
+renderer = ShellRenderer

powerline/renderers/tmux.py

@@ -39,3 +39,6 @@ class TmuxRenderer(Renderer):
 				else:
 					tmux_attr += ['nounderscore']
 		return '#[' + ','.join(tmux_attr) + ']'
+
+
+renderer = TmuxRenderer

powerline/renderers/vim.py

@@ -9,6 +9,7 @@ from powerline.theme import Theme
 
 import vim
 
+
 vim_mode = vim_get_func('mode')
 vim_getwinvar = vim_get_func('getwinvar')
 vim_setwinvar = vim_get_func('setwinvar')
@@ -120,3 +121,6 @@ class VimRenderer(Renderer):
 					attr=','.join(hl_group['attr']),
 				))
 		return '%#' + self.hl_groups[(fg, bg, attr)]['name'] + '#'
+
+
+renderer = VimRenderer

powerline/renderers/zsh_prompt.py

@@ -11,3 +11,6 @@ class ZshPromptRenderer(ShellRenderer):
 	@staticmethod
 	def escape(string):
 		return string.replace('%', '%%').replace('\\', '\\\\')
+
+
+renderer = ZshPromptRenderer

tests/test_configuration.py

@@ -81,9 +81,8 @@ class TestConfig(TestCase):
 		from powerline.segments import common
 		from imp import reload
 		reload(common)
-		from powerline.shell import ShellPowerline
+		from powerline import Powerline
 		with replace_module_attr(common, 'urllib_read', urllib_read):
-			from powerline import Powerline
 			Powerline(ext='wm', renderer_module='pango_markup').renderer.render()
 		reload(common)
 

tests/test_lib.py

@@ -1,5 +1,5 @@
 # vim:fileencoding=utf-8:noet
-from powerline.lib import mergedicts, underscore_to_camelcase, add_divider_highlight_group, humanize_bytes
+from powerline.lib import mergedicts, add_divider_highlight_group, humanize_bytes
 from powerline.lib.vcs import guess
 from subprocess import call, PIPE
 import os
@@ -8,10 +8,6 @@ from tests import TestCase
 
 
 class TestLib(TestCase):
-	def test_underscore_to_camelcase(self):
-		self.assertEqual(underscore_to_camelcase('abc_def_ghi'), 'AbcDefGhi')
-		self.assertEqual(underscore_to_camelcase('abc_def__ghi'), 'AbcDef_Ghi')
-
 	def test_mergedicts(self):
 		d = {}
 		mergedicts(d, {'abc': {'def': 'ghi'}})