Wrap test framework dependency, change to Minitest

* Change to use Minitest instead of Test::Unit. It replaced Test::Unit
  in the stdlib in v1.9, so might as well use it explicitly.
* Added a Fastly::TestCase class that wraps Minitest and updated
  the existing classes to use this wrapper. This enables the framework
  to be changed easily at a later date if required.
* Removed the inline calls to require RubyGems and Test::Unit.
* Removed the file munging for requiring {common,helper}.rb - using
  Rake::TestTask sets the load path correctly and also allows
  individual tests to be run.
* Added a test against the Minitest version to accommodate >= 5 for the
  Fastly::TestCase class.
Map method name inconsistency with an alias
Add conditions to the loop of methods generated in fastly.rb
Unbreak listing things
Work on getting request settings in
Closer with request settings
Fix up request settings further, start on cache settings
More on cache settings
Headers
gzip and response object
Fix dumb typo
Brush up gzip and headers a bit, in-progress documenting options
Finish documenting options
Add some tests
Adding in s3 logging
Dur
Merge s3 logging into this branch, may require some changes
Document s3 logging options and methods
Merge branch 's3-logging' into fix_s3
Document new object methods