Add PostgreSQL 9.5 to standard PostGIS 2.2. battery version tests

[robe]

PostgreSQL 9.5 has reached feature freeze as well and released their first alpha. That means debbie's been testing 9.6 instead of 9.5 this past week.

I've create da separate branch for 9.5 test now that rebuilds on git change of 9.5 and tests.

Just need to also add 9.5 to our 2.2 battery for testing.