Clean environment for test runs and jetpack script
Make spec suite more resilient to dirty checkout
Fix web specs

- Rack spec was running on commonly occupied ports
- Web spec was angry about debug messages on stderr
Check for jruby, not just ruby
Actually run reloading spec

File extensions. Yep.
Disable failing parts of reloading spec

cc @sul3n3t looking at the original PR
(https://github.com/square/jetpack/pull/33) I strongly suspect that
these tests never actually ran. Let's take a look when you have a chance
and make sure the desired behavior is tested.
Add Travis CI
Simplify script/ci to work with Travis CI
Invoke rake correctly

Invoking `bin/rake` directly only works if your environment is set up to
use the correct ruby. Otherwise, we should use the right ruby explicitly
with `bin/ruby bin/rake`.
Rake must be in the Gemfile to build a binstub
Clean up additional files generated during spec runs
Use java from settings everywhere

Previously the 'java' setting was only used in the launch script, which
could result in different versions of java being used for launch vs.
rake/console.
Fix spec expecting a non-existent java version