Supporting changes for TISTUD-3814 Alloy: add hover info for element names in Alloy .xml file
  - Move deprecated property up model type hierarchy to BaseElement
  - Allow JSModelFormatter to take in BaseElements so we can pass in a TypeElement and get a somewhat decent hover.
  - fix broken behavior due to changes for TISTUD-5648
  - Add unit tests around BuildPathManager
  - Make the BuildPathManager methods take in IBuildPathEntry, not impl
  - Make the BuildPathManager methods return booleans rather than nothing
Merge pull request #153 from sgtcoolguy/TISTUD-3814

Supporting changes for TISTUD-3814 Alloy: add hover info for element names in Alloy .xml file