#158 - Moved the osx packaging.

Move was done from ant to buildr.
Also, there was a bug where the log file of server in mac would stay in the
same installation directory instead of going to '/Library/Logs/Go Server.app/go-server.log'
#158 - Removed the ant scripts used to build osx installers.
Merge pull request #187 from bsharanya/master

Moved OSX Packaging from ant to buildr