IDEA-104500 Gradle: Allow to reuse common logic for other external systems

1. Gradle 1.6 is applied;
2. GradleStartupActivity is restored;
3. GradleProjectResolverExtension contract is changed - it's possible to completely overwrite data model now;
do not report "no tests were found" when root is a test itself
copyright: insert copyrights for new files created in IDEA only (IDEA-105188)
javafx: unused imports inspection (IDEA-105391)
javafx: index to reject non-javafx projects (IDEA-105628)
OrderEntryUtil.processOrderEntry method added
EA-45330 - assert: XmlUnusedNamespaceInspection.getLocationReferences
EA-36270 - assert: FocusManagerImpl.getFocusOwner