fpc 2.6.4 (new formula)

Here is a new formula for [Free Pascal](freepascal.org) compiler.

Never been a serious Pascal user, I can't tell if this formula is in usable status for regular FPC users, but at least it worked for me when compiling some legacy Delphi code. I just didn't want to install `.pkg` on Mac.

Mostly followed [this install guide](http://wiki.lazarus.freepascal.org/Installing_Lazarus), especially for Linux section. Perhaps more discussion would be needed for Lazarus/Xcode integration, which I'm not very knowledgeable about.

Tested on Mac OS X 10.7.5 and 10.9.4.