Update brew installation commands

As near as I can tell, `brew install python` now
 * Installs python as a framework-style build by default
 * Adds appropriate symlinks for `python`, etc. to `/usr/local/bin/`
 * Doesn't appear to install anything under `/usr/local/share/python` besides some demo items under `share/`

As such, I believe the directions I deleted are no long applicable.

Would appreciate others' feedback on my findings / assumptions here. Cheers!