Merge pull request #99 from krono/pharo2.0

Add trait support for filetree, partially fixes #11, pharo 2.0 part(cherry picked from commit 4d56009df40b119b2b2009d84c4ce1324c2ed251)

Conflicts:

	repository/MonticelloFileTree-Core.package/MCFileTreeAbstractStWriter.class/methodProperties.json
	repository/MonticelloFileTree-Core.package/monticello.meta/version
	repository/MonticelloFileTree-Tests.package/monticello.meta/version