added JCenterPluginMapper, which retrieves plugins from Bintray by the gradle-plugin-id attribute value on the package name
reverted deletion
take latest version from package information
instead of relying on natural sorting
anonymous search works, workaround removed.
jcenter removed as it is now a remote in repo.gradle.org
Merge pull request #217 from jbaruch/master

Add a JCenter based plugin mapper.