Enable MySQL and Postgres on Travis.ci
Travis: add Ruby 2.0.0, and require passes for rbx and jruby in 19 mode.
Fix adapters for MySQL and JDBC.
Use float instead of double as column type for the database inserter.

This is more standards complaint, and should fix some failing PG specs.
Fix another spec related to double/float
Fixed merge conflicts in gemspec
Merge pull request #141 from wvanbergen/enable_databases_for_travis

Enable MySQL and Postgres on Travis CI builds