Use hex strings for RGB colors in colorschemes

Previously you'd have to convert a hex number to an integer, this change
makes it possible to use a hex string instead which is much more useful.

docs/source/configuration.rst

@@ -99,9 +99,9 @@ Colorschemes
     color, and the value is one of the following:
 
     * A cterm color index.
-    * A list of two integers, where the first integer is a cterm color 
-      index, and the second is an RGB/hex color. This is useful for 
-      colorschemes that use colors that aren't available in color terminals.
+    * A list with a cterm color index and a hex color string (e.g. ``[123, 
+      "aabbcc"]``). This is useful for colorschemes that use colors that 
+      aren't available in color terminals.
 
 ``groups``
     .. _config-colorscheme-groups:

powerline/colorscheme.py

@@ -12,7 +12,7 @@ class Colorscheme(object):
 		# Create a dict of color tuples with both a cterm and hex value
 		for color_name, color in colorscheme['colors'].items():
 			try:
-				self.colors[color_name] = (color[0], color[1])
+				self.colors[color_name] = (color[0], int(color[1], 16))
 			except TypeError:
 				self.colors[color_name] = (color, cterm_to_hex[color])