Promote the OO interface

This involves:
* Having a 'new' method in Test::Compile which actually creates a
  Test::Compile::Internal object
* Updating the Test::Compile POD to include all the methods provided
  by the Test::Compile::Internal object
Tidy up the tests to reflect the new importance of the OO interface
Default to being verbose

Previously, Test::Compile was verbose, but Test::Compile::Internal
was not.