Fix ruby engine detection such that it detects Ruby 1.8.7

Based on bundler's ruby engine detection:

https://github.com/carlhuda/bundler/blob/438ef20987951883cb5837d245eac9c517848b2d/lib/bundler/ruby_version.rb
Add note on how to build the jar and bundle
Add rake development dependency

This allows you to run:

    bundle exec rake

Before this change, this command failed with the error:
Gem::LoadError: rake is not part of the bundle. Add it to Gemfile.
Add Travis CI configuration file
Add Travis CI badge to the top of the README
Consistenly use double quotes in Rakefile
Cleanup trailing whitespace
Merge pull request #23 from sferik/travis-ci

Add Travis CI
Add Rake to Gemfile.
Bundle with development for travis and remove rake from Gemfile.
Merge pull request #7 from nate/bugfix/ruby-1-8-7-detection

Fix ruby engine detection such that it detects Ruby 1.8.7
Merge pull request #24 from thedarkone/no-unsafe-chmv8

Added a "sun.misc.Unsafe-fee" TS::Cache JRuby backend
Use the "factory" method to get keys.
Rescue from NoMethodErrors when objects "lie" about responding to <=>.

Fixes #19.
Bump TreeNode threshold.

Using TreeNodes means going into Ruby-land, which is actually slower than extra long Node linked lists.