support varargs string syntax for dependencies in Aether
moved the notion of ExcludeResolver from the release plugin into core so that both Aether and Ivy implementations exist
add notion of exported to API
fix passing of exclusion rules from Aether dependency to grails one
Aether: Fix propagation of transitive and exported settings in dependencies
Aether: add handling of 'export' as well as 'exported'
use 2.3 compatible release plugin
update h2 version
update slf4j version
upgrade Groovy version to 2.1.2
Revert "upgrade Groovy version to 2.1.2"

This reverts commit 80a8b566fe5c1c4cdcc791ef1ed0e27667e7f298.