Add generator specs and fix cosmetic indentation issue

[seancribbs]

This adds specs for all included Rails generators and fixes a minor cosmetic issue related to existing indentation in the test/spec helpers as described in #232.

Along the way, some issues were identified with the test server, including missing a trailing slash on PIPE_DIR and some incompatibilities in the KV backend introduced in the upcoming 1.1 release.

Other salient points:

• Adds development dependency on ammeter gem.
• Generator specs will generate into ripple/tmp.
• Guard runner now recognizes generators, templates and their specs and includes 1.9.3 in the rvms.
• spec/support/test_server.yml is found via expand_path and __FILE__ instead of relying on relative path

I would prefer a Basho employee review the test backend changes, a committer familiar with Rails/RSpec review the generator changes.

[ntalbott]

Had a read-through: +1.

[myronmarston]

I made a few comments, but it looks good otherwise.