Clean up Vundle

I did some clean up on my vimrc regarding Vundle.

* First of all, now Vundle uses begin/end calls instead of rc.
  Plugins are loaded between begin call and end call. After
  updating my Vundle submodule begin and call started working.
  I still have to study whether this makes my vimrc more
  compatible with Windows or not (like if I give a f**k).

* Organize the way Vundle plugins get loaded. Instead of just
  infinitely adding them to vimrc, I've somehow categorized calls
  to Plugin. Colorschemes, language supports, and a generic
  category for plugins that I wouldn't know how to classify.

* Lotsa new plugins, specially colorschemes.
Organize vimrc structure

Better comments, table of context, organize commands in sections
based on what does the command do... NEED MOAR CLEANUP, DUDE.
MOAR CLEANUP

Changes done by the clean-up:

* Organize the contents of vimrc file. Format comments, manage
  sections and subsections and remove old and dusted lines that
  were outdated and unused anyway.

* Colorschemes: moved to vimrc so that they can be applied to
  terminal too. A safety check was added. Colorscheme will only
  be applied if terminal supports 256 colors (most desktop
  terminal emulators supports them these days... except Windows).
  Also, syntax is only enabled if terminal supports multicolor.

* Fonts: I just learnt that you can chain multiple fonts inside
  a guifont setting. If first font is not installed, it will try
  with second font, and so. Default Vim-GTK/Linux font is now
  Ubuntu Mono. In case it's not installed it'll fallback to
  DejaVu Sans Mono; I think it's installed by default in 99% of
  Linux distributions. This change makes old ubuntu-tweaks Git
  branch useless.

* Maps: I learnt about maps and I love them. Add some maps for
  useful things like moving windows or toggling NERDTree.

By the way, new preferences. Colorscheme has changed to Wombat.
Also, I'm finally giving in for Menlo font instead of classic
Monaco in my Mac. Thus, MacVim now uses Menlo by default.
I've got a plan on making my settings more computer agnostic by
moving all these personal preferences to a different file and
then sourcing it from .vimrc.