imagemagick formula with perl and gs

This is my first pull request, so hopefully I'm doing it mostly right.

These are my "brew edit imagemagick" edits to allow brewing ImageMagick 6.8.0_10 on Lion and Mtn Lion with PerlMagick and Ghostscript functionality. Install command:

brew install --fresh imagemagick --with-fontconfig --with-ghostscript --with-jasper --with-librsvg --with-libtiff --with-little-cms --with-quantum-depth-8

Confirmed this works on OSX 10.7 Lion and 10.8 Mtn Lion.