Try a potential fix for Weblogic workaround

It appears that the context is sealed when we enter the static initializer of
RhinoHelper; try and fix it by _not_ sealing the context.
Change release notes
1.2.1
Depend on jackson-coreutils 1.7

Fixes problems with classloading.
Update version and jackson-coreutils dependency
Add a missing schema key...
1.2.3
Merge branch 'v1.2'

Conflicts:
	RELEASE-NOTES.md
	project.gradle