Update solarized to use the same condition and terminal colors as vim-colors-solarized

When using vim from a terminal or terminal emulator, the colors in the solarized themes do not match the colors from [vim-colors-solarized](https://github.com/altercation/vim-colors-solarized). This pull request updates the themes to use the same terminal colors as the authoritative theme as well as use the same condition to decide which set of colors to use.