Use NONE when no attribute is set
Minor color updates
Update Python colors
Update Python syntax colors
Merge branch 'master' of https://github.com/Lokaltog/vim-distinguished into develop

* 'master' of https://github.com/Lokaltog/vim-distinguished:
  Add color scheme
Add support for GUI vim
Update CursorLine and ColorColumn colors
Update vertical split color
Create colors for HighlightTags
Update MatchParen colors
Update Search and Syntastic highlighting
Give CursorLine better visibility
Add StorageClass highlighting
Use black as default background color
Fix CursorLine color

Closes #4.
Add CursorLineNr highlighting

Closes #3.
Add Operator highlighting
Customized for my own need.
Modify README.md.
Darken inactive tabs to make the active tab more distinguishable