add ugly #hasChildren API to tree
use ugly #hasChildren API
more ugly tree #hasChildren hacks (it's called API)
addressed ben's remarks
addressed ben's remarks
Merge branch 'feature/tree-hasChildren' of https://github.com/camillobruni/spec into camillobruni-feature/tree-hasChildren

Conflicts:
	Spec-Core.package/monticello.meta/version
	Spec-MorphicAdapters.package/monticello.meta/version
Small pass over Camillo's code