Allow including external projects

[Faithcaio]

Adding userplugins=true to project.properties enables testplugins/userPluginBuilds file to add paths to additional gradle projects

/path/to/my/plugin/project

testplugins/userPlugins file to add plugins as gradle dependencies

com.example.plugin:plugin1
com.example.plugin:plugin2

Sponge Plugins added this way are automatically loaded and can be hot-swapped.

[aromaa]

Personally I would rather not alter the build scripts just for this and avoid the extra LOC. I don't think this even saves a lot compared to doing it the traditional way of appending the classpath in the IDE itself.