Made wildmode work similar to bash/zsh

Now, a second press of the tab key will go through the different full
completions, instead of needing to press <c-n>/<c-p> to move through the
wildmenu.
Changed the colorscheme to solarized

rdark is not a very good colorscheme and a lot of the colors are
repeated. solarized looks much better, but it does not run at it's best
in the terminal. So I changed the colorscheme only in gvim.