[ViM] Some vimrc changes
[ViM] Always use Rainbow Parenthesis inside C files
Fix typo in README
[ViM] Add some comments to the vimrc
[ViM] Airline Settings changes

We use vim-airline not powerline. Hence, change the comment and remove
ancient code referencing Powerline settings.
[ViM] Hardmode changes

Remove the hardmode plugin since we never really use it.
Also remove all the relevant code snippets configuring it.
Add new remappings to prevent use of arrow keys in insert mode too.
[ViM] Large change to Plugins

* Replace 'plasticboy/vim-markdown' with 'gabrielelana/vim-markdown'
which has more markdown features than just a syntax colouring.
* Replace 'wipeout' with its git repository at 'artnez/vim-wipeout'

* Add 'tpope/vim-git' plugin which adds some git commands, better
filetype detection for git files and improved syntax highlighting
* Add 'SirVer/ultisnips' a plugin for adding code snippets very easily
into buffers
* Add 'honza/vim-snippets' plugin which adds a binch of snippets fot
ultisnips to use
* Add 'xolox/vim-colorscheme-switcher' and its dependency
'xolox/vim-misc' plugins

* Remove 'Yggdroot/indentLine' plugin since I don't like it or need it
anymore.
* Remove 'airblade/vim-gitgutter' plugin. It slows down vim and causes
some problems. Anyways, I don't need that kind of detail
* Remove 'wikitopian/hardmode' plugin which was disabled in the last
commit.

* Shift 'godlygeek/tabular' to main plugins instead of LaTeX
* Move 'sk1418/blockit' to list of disabled plugins
* Move 'scrooloose/nerdtree' to list of disabled plugins
* Move 'mrtazz/simplenote' to list of disabled plugins. I like the
plugin but haven't really used simplenote in a while. In case I ever
need to use Simplenote again, I'll enable this.
* Move 'valloric/YouCompleteMe' to list os disabled plugins. It's too
huge and sometimes gets in the way. Plus I realize that I don't like
syntax completion when I'm programming. It's a very distracting feature
[ViM] Configure some plugins

* Bind <F6> to create the Tagbar split window
* Bind <leader>r to toggle rainbow parentheses

Add tagbar settings, to show linenumbers and autoclose when moving to a
certain tag