Experiment with integrating the Gradle tooling library

I seem to be able to get project (source) dirs, at least, but
nothing seems to list classpath correctly... :(
Refactoring... STILL refuses to work :(
Minor refactor; add get-dependencies method

Interestingly, get-dependencies actually works for a non-android
gradle project I have.... Weird
Add build.gradle for testing

It appears that the tooling works very well... unless you happen
to be using the android plugin. Lovely.
Add a with-gradle macro... for fun
Use the syntax quote for the macro
Fix macro; experiment with calling dependencies task
Add wacky function to extract dependency coords from task output

Works surprisingly well, though we still have to map the coords
to local cache (and deal with aars...?)
Add gradle-classpath method for a wacky way to resolve jars

This is definitely not to be prefered to (get-dependencies),
but it's a potential option for Android projects which refuse
to give us their classpath the normal way
Refactor gradle namespace a bit; restore test case
Merge branch 'gradle'