Merge pull request #442 from ovatsus/master

Optionals Refactoring & Fixes
Merge pull request #444 from ovatsus/master

224 + 441
Merge pull request #446 from ovatsus/master

Json + Freebase fixes
Update SignatureTests.fs
Update RELEASE_NOTES.md
Doc fix
Merge pull request #450 from ovatsus/master

Fix Path property showing up (closes #449)
Fix UTs