Removed unused class.
Added DefaultGradleConnector.daemonBaseDir() to allow the tooling API client to specify the daemon base dir to use. Only supported for >= 2.2 and is internal.
Changed the tooling api tests to use the same daemon base dir as the other int tests, for those Gradle versions where it is supported. This means that more stuff will end up under build/daemon instead of intTestHomeDir/...
Added @Incubating
Changed GradleBuild to extend Model.
Moved some logic from ToolingApiSpecification to ToolingApi fixture. Fixed execution when tests are in forking mode to actually use forking mode.
Added a task to probe for daemons left running after the int tests have completed. Currently just logs some diagnostics. Next step will be to use this to clean up the daemons.

Moved 'cleanUpCaches' task so that it lives in the root project and so runs once per build rather than once per project.