Add Support-Map Tests for Rhino

[dhaber]

This patch adds Support Map Tests to the rhino test suite. It makes the following changes:

1. Add compiled version of source-map (version 0.1.31) because Rhino can't dynamically pull in dependencies
2. Add source-map to the Rhino build with a Header/Footer that wraps source-map as a less-friendly dependency
3. Add hooks in RhinoTest to support per-test bootstraping and validation
4. Add a SourceMapRhinoTest that bootstraps SourceMap tests and then validates them after they run
5. Update lib/less/rhino.js to properly handle (some) source-map options and add a new one (--source-map-output-map-file) that will output the source-map to a separate file (so we can validate our Rhino tests)
6. Add a new testRhinoSourceMap and add it to the test list

Also makes some minor bug fixes:
A. Fix typo in the Gruntfile.js for the sourcemap-test
B. Update Gradle build to always build the less-rhino-.js before running the tests
C. Remove unused callback in less-test.js

[SomMeri]

Thank you a lot.

[SomMeri]

@dhaber One of your changes have been conflicting with recent changes in less.js. It is in test/index.js file . I used less.js version, so let me know if it was wrong. For convenience, link to current index.js file

Thank you again for all pull requests.

[dhaber]

@SomMeri - np - Thank you! I've only tested against the pre=merge branch so we should re-run all tests against the latest and confirm that all of the tests still pass.

[SomMeri]

@dhaber I tried and jshint complained a lot #15. I fixed rhino.js today and will continue tomorrow if I find the time.

If you will continue in the meantime, let me know so we do not work on the same thing. I would find something else to do in the meantime then.