Updated Readme

Now includes installation instructions for OSX, and added small chunk
on a Date/Time related error I get when trying to run a local copy of
the server.
Updated Readme

Moved the macports URL to a more sensible place
Updated README

Added macports hyperlink
Updated Readme

Changed from php 5.6 to php 5.5
Merge pull request #183 from dstansby/master

Updated README for OSX