Updates to git submodules, third party libraries

Removed git submodules for third party libraries, and switched to using
source tarballs. Completed the rename of ChemData to MongoChem in the
source tree. Added Open Babel and VTK to the superbuild.

Change-Id: I8a17ac432f62d0c5f85a4aef3545e7efd48c0a5c
Merge branch 'submodule-updates'

Change-Id: Ic874e62c6ed1b7ff6a76ee59569397425989080a