Add tips & tricks to the docs

Closes #182.

docs/source/index.rst

@@ -9,6 +9,7 @@ Powerline
    introduction
    overview
    configuration
+   tipstricks
    fontpatching
    license-credits
 

docs/source/tipstricks.rst

@@ -0,0 +1,37 @@
+*************
+Tips & Tricks
+*************
+
+Vim
+===
+
+Fix terminal timeout when pressing escape
+-----------------------------------------
+
+When you're pressing :kbd:`Escape` to leave insert mode in the terminal, it 
+will by default take a second or another keystroke to leave insert mode 
+completely and update the statusline. If you find this annoying, you can add 
+the following snippet to your :file:`vimrc` to escape insert mode 
+immediately:
+
+.. code-block:: vim
+
+   if ! has('gui_running')
+       set ttimeoutlen=10
+       augroup FastEscape
+           autocmd!
+           au InsertEnter * set timeoutlen=0
+           au InsertLeave * set timeoutlen=1000
+       augroup END
+   endif
+
+Useful settings
+---------------
+
+You may find the following vim settings useful when using the Powerline 
+statusline:
+
+.. code-block:: vim
+   
+   set laststatus=2 " Always display the statusline in all windows
+   set noshowmode " Hide the default mode text (e.g. -- INSERT -- below the statusline)