Support version 1.9.2 and 1.9.3 of ruby

[punkle]

• Also change travis config to run tests against these versions.
• Fixed one test which had not previously been failing.

[zachfeldman]

Hey @punkle looks like 1.9.2 tests are failing: https://travis-ci.org/zachfeldman/rubypress/jobs/31978997

Any ideas?

[zachfeldman]

Also, thanks for your work thus far!