Renamed ExternalResource.read() to withContent().
update to tooling API spec
Expose information about a project's build script via the tooling API.

- Added GradleProject.getBuildScript() method.
Mention the tooling API changes in the release notes.
Some tweaks to AbstractMultiTestRunner hierarchy.
Reworked AbstractMultiTestRunner so that it allows subclasses to filter individual tests instead of test classes.