Making point and geometry data save properly

Post_* Models now save values but still need to update Posts API.
* Override save() and _build_select() ORM functions to use
  GeomFromText() and AsText() MySQL functions. This gives us WKT strings
* Override get() and set() in Model_Post_Point() to decode WKT and return
  an array of with lat/lon values
* Add test cases for Post Point Model (using PHPUnit DataSets)
* Add test cases for Post Geometry Model (using PHPUnit DataSets)
* Extend Unittest to fix DSN for db connection
* Extend Unittest to fix foreign key errors when truncating tables
* Including GeoPHP submodule for WKT support
Improve other tests model tests with simpler exception test

Also change Post test to extend Unittest_Database_TestCase and use
PHPUnit Datasets as form creation seemed to have been broken by
other DB tests.