Added new languages plugins and colorscheme

- Added plugin for improved php support
- Added plugin for rust
- Added 'Atom' colorscheme
Changes on vimrc (and gvimrc)

- Little change on gvim font priority
- Tweaked vimrc a little more for some graphical cues and personal
  preferences
- Reenabled backup and added 'undo directory' for improved 'undo'