gretty-plugin: graceful handling of non-gretty overlay sources
gretty-plugin: simplified onStart/onStop events - no call to overlay-source event handlers.
gretty-plugin: introduced gretty events onScan and onScanFilesChanged
gretty-plugin: introduced scanning on webAppDir of the current project and it's overlay sources; improved logging.
gretty-plugin: implementing hot-deployment for jettyXXXWar tasks.
gretty-plugin: implementing hot-deployment for jettyXXXWar tasks.