More robust mimetype detection using Apache Tika.

Tika is what is being used by Modeshape, too, and provides
file extension and magic-bytes based detection.

When generic document artifacts are uploaded, their mimetype is properly
detected and not merely defaulted to application/octet-stream.
Mimetypes are now determined on the server, ignoring ahy hints sent up by the clients.
resolving merge conflicts
reducing permgen setting
Merge pull request #222 from KurtStam/master

reducing test memory foot print
reducing permgen setting
Merge pull request #223 from KurtStam/master

reducing test memory foot print
reducing permgen setting
Merge pull request #224 from KurtStam/master

reducing test memory foot print
reducing permgen setting
Merge pull request #225 from KurtStam/master

reducing test memory foot print
reducing permgen setting
Merge pull request #226 from KurtStam/master

reducing test memory foot print