Comment out some mappings which has same function as unimpaired.
This aims to broaden namespace for other mappings.
Remove the mapping to editting build file and add mappings to editting and sourcing .vimrc.bundles.
If the number of files of .vimrc.* increase in the future, map <Leader>e* and <Leader>s* to them.
Map <F5> to toggling background color.
This is mainly for solarized colorscheme.
Comment out some mappings which has the prefix <Leader>c.
This is same as quickfix operation mappings.
Replace comma with space key as a mapleader.
The first reason to do so is that the space key can be touched by both hands.
It means that any preceding key is accepted.
The second reason is that the default function of the space key is unfolding.
I seldom use folding and unfolding functions, so these functions are mapped to other key sequences.
The third reason is that the default function of the comma key is sometimes useful.
Comment out mapping S to :%s//g because of the compatibility with Vi.
Modify some mappings to be more reasonable.
In normal mode, ctrl-b is used to scroll backward, so remap ctrl-h to redraw and switch off highlight.
Also backspace is used to move left in normal mode, remap backspace to normalize spaces.