Initial
Better support for indentation options

Add functions SeIndentHard, SeIndentSoft and SeIndentMixed to set
correct indentation options (et, sw, sts, ts) for using, resp., all hard
tabs, all spaces and mixed tabs & spaces, to indent.
Each of these has a 'Setl' counterpart (eg. SetlIndentSoft) that only
sets the buffer-local options.
Add 'Maintainer' header to vimrc
Ask to delete unused bundle directories
Handle Git Submodules
Ignore .netrwhist
Replace plugin 'nerdcommenter' with 'tcomment_vim'
Trim settings for clang_complete
Refactor vimrc
Map <Up> and <Down> to move by screen lines
Add plugin 'ultisnips'
Correct a few plugin's URLs
Unmap <Up> and <Down>

Mapping to g<Up> and g<Down> breaks movement in (completion) popup menu in Insert mode.
Change g:syntastic_c_compiler_options

Assume C99 as the default language standard.