Enable both GNU and OS X `ls` commands to use Solarized colorscheme.

Hi Mathias, I added capability for the `ls` command to utilize the Solarized color scheme, like the
rest of your repo. Let me know what you think.


File:       .aliases

For GNU `ls`:

Replace LS_COLORS environment variable export with values that represent
Solarized colorscheme.

For OS X `ls`:

Add export of LSCOLORS environment variable with values for Solarized.