Doc : improved Copy task VS copy() method chapter
GRADLE-2171: Added fail and warn strategies to DuplicatesStrategy.

- WARN will log a warning message for each duplicate file that is encountered.
- FAIL will throw a DuplicateFileCopyingException.
- Updated documentation and unit tests to reflect these new behaviors.
GRADLEREV-16 - Rename TestReports to TestTaskReports.
GRADLEREV-21 - Move JCenter constants off the public API.
GRADLEREV-22 - Standardise on “JCenter” (vs. jcenter) in user guide.
GRADLEREV-24 - typo in Javadoc.
GRADLEREV-25 - @Incubating should not be @Inherited
GRADLEREV-26 - mention string to enum coercion in the DSL reference.
Checkstyle fixes.
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.
Added a little bit of coverage.
Added a TODO
Added a bit of logging.
Some refactoring. The new resolution result can be built lazily.
GRADLE-2743. Merged code from what appears to be the original source http://svn.apache.org/repos/asf/ant/ivy/core/trunk/src/java/org/apache/ivy/plugins/parser/xml/XmlModuleDescriptorParser.java so that ivyauthor and repository elements do not cause a Gradle validation error.