add jCenter() repository shortcut for Bintray's JCenter
Add jCenter repository for Aether
Update RepositoriesConfiguration.groovy

> "jcenter" a la Gradle
Update RepositoriesConfigurer.groovy

> "jcenter" a la Gradle
Update Ivy resolver tests for "jcenter" repo
Update Aether resolver for "jcenter"
Standardizing to "jcenter" in Ivy resolver
Standardizing to "jcenter" in Aether resolver
Merge branch 'master' of github.com:grails/grails-core
Merge branch 'master' of github.com:danveloper/grails-core
fix for GRAILS-10975: throw primary LinkageError instead of secondary ClassNotFoundException
Fixes for GRAILS-10977
Merge pull request #437 from danveloper/master

add jCenter() repository shortcut for Bintray's JCenter
Fix for GRAILS-10973: Content negotiation chooses first available withFormat choice for "all" format instead of the * choice
Fix for GRAILS-10973: Fix default Config.groovy: default format should be the first key in grails.mime.types
fix for GRAILS-10947 “Lost dependency artefact type for grails plugins in pom.xml”
Merge branch '2.3.x' of github.com:grails/grails-core into 2.3.x
Merge pull request #446 from jdbeutel/2.3.x

fix for GRAILS-10975: throw primary LinkageError instead of secondary Cl...
Merge pull request #450 from sbglasius/GRAILS-10977

Fixes for GRAILS-10977 (against 2.3.x)
Fix for GRAILS-10897: wrong content negotiation in a unit test