POD fixes; code samples are now rendered as code.
Improved POD to include BASE and SIGNATURE usage.
Makefile.PL should not be executable.
Added minimum perl version, removed unused Modern::Perl dependency.
Added missing test file to MANIFEST.
Added TEST_REQUIRES.
Updated prereqs using App::Midgen
Merge pull request #1 from mbeijen/makefile-pod

Fixes to Pod and Makefile.PL