Adding support for compressed DB files

Adding support for .gz and .bz2 compressed DB files.

DB files must be in the form:
DB_NAME.sql.gz|bz2
One database file per compressed file
Merge pull request #42 from dhensby/pulls/db-compression

Adding support for compressed DB files
Adding optional php-mcrypt provisioning for php versions < 5.4
Merge pull request #46 from camfindlay/patch-2

Add php-mcrypt to php extensions
Make sake globally accessible

Allows users to simply run "sake dev/somecommand" in the webroot.
Merge pull request #48 from camfindlay/globalsake

Make sake globally accessible