Support for external color themes

[martin-svk]

Hi,

I know there is an option to directly edit cvimrc css files, but I guess You have to have some talent to make it look good.

I think about shipping cvim with some default dark and white themes and to be able to add some more externally (solarized, molokai, etc.).

That could be configurable using the colorscheme option in cvimrc.

[DuckyDaDuck]

would be nice to see palenight aswell since im currently using the clean palenight theme off the chrome store