update groovy version to 2.3.0-beta-2
fix failing tests that relied on presence on standard taglib jar
fix for GRAILS-11292 "Unable to create-app when mavenRepo credential declared in ~/.grails/settings.groovy"
GRAILS-11314 Fix @Value in unit tests
Revert some changes made by 50c5a666 to JSP tests
refactor grails-web-jsp to support standalone usage, get rid of xpp dependency
use GrailsPlaceholderConfigurer and MapBasedSmartPropertyOverrideConfigurer in unit tests
execute all bean definition closures at once in GrailsApplicationTestPlugin
change references to normal refs
make GrailsWebApplicationContext support resolving GrailsApplication instance in tests
GRAILS-11314 Fix @Value in unit tests: use OptimizedAutowireCapableBeanFactory for GrailsWebApplicationContext by default
use Spring 4.0.3.RELEASE
add support for "redirect:" views in standalone GSP
GRAILS-11296: When page removed from pageCache, clear metaClass

When GroovyPageMetaInfo is removed from the pageCache, remove the metaclass from the pageClass in the GroovyPageMetaInfo.
Merge branch '2.3.x'

Conflicts:
	grails-web/src/main/groovy/org/codehaus/groovy/grails/commons/spring/GrailsWebApplicationContext.java
createAndRegister() does already register the listener.
removed duplication.
improved readability, moved noisy context handling to methods.
more readability, moved functional test base url cleanup to method.
more readability, moved waiting for server to method.