fix failing integration test on unknown os
Selection rules should not apply to parent poms

+review REVIEW-5253
Include documentation on plugins {} block from plugins.gradle.org in user guide

+review REVIEW-5255
Include documentation on plugins {} block from plugins.gradle.org in user guide

+review REVIEW-5255
Add missing extensions of Model interface

+review REVIEW-5254
Remove false extensions of Model interface

BasicGradleProject is not a model that can be fetched through the Tooling API's org.gradle.tooling.ProjectConnection#model

+review REVIEW-5254
Revert: Remove false extensions of Model interface

BasicGradleProject can be fetched as a model through a BuildAction

+review REVIEW-5254 (reverted from commit 1e9a65d2cfd609fd037f1c7d6766dbd8a58e7783)
Add missing override for withCancellationToken

+review REVIEW-5254
Add missing override for APIs from LongRunningOperation

Overrides are required to allow fluent-style builder usage.

+review REVIEW-5254
Consistent order of method overrides for all LongRunningOperation implementations

This commit only rearrange the methods for consistency but does not make any API changes.

+review REVIEW-5254
Improve generics with respect to builder pattern / fluent API

Achieved through applying generics recursively.

+review REVIEW-5254
initial setup on play sample
declare play version (version+scala variant) in play component
use https to resolve javadoc packages from oracle; http is no longer working
reference java api 1.6 and not 1.5 in javadoc
Fix checkstyle

Restricting the names of generic types to single letters seems overly strict to me.

+review REVIEW-5254
Show cmd line info on 'gradle help --task <task>'

Info is shown when invoking 'gradle help' on the cmd line.

+review REVIEW-5256
tweak play sample integtest to tweak the correct build.gradle file for using forked compiler
Changed int test cleanup to clean up cached state for old versions of Gradle whose cache implementations are not multi-process safe.
Changed `ComponentReport` to use the model registry to find all of the stuff it needs, instead of using extensions.