Clarify PHP, MySQL sysreqs on installer first page
Add installer model with 256-bit secureHash generation method.
Add boolean tests required for installation.
Add phpdoc for `Bts_Model_Installer::testEnvironment()`

- also rearranged mcrypt line
Add test results page
Improve presentation of test results.
Add styling to tests page

- Reformatted CSS
Move readable text into Installer model
Add OpenSSL to extension check in Installer model.
Adjust views in installer to fix buttons on Test page