A bunch of changes:

* New plugin 'Join'.
* New colorscheme 'seoul256' & 'zenburn'.
* Cleaned up my cpp settings in cpp.vim.
* Deleted cscope_maps.vim, currently non need for it.
* Updated vimrc
    * Updated the prelimilary comment section.
    * Added configuration for plugin 'syntastic'.
    * Updated configuration for plugin 'youcompleteme'.
* New plugin 'gitgutter'
* New colorscheme 'atom'