Merge pull request #94 from andylyall/develop

Develop
The earlier patch to test for a null image class was not forwarded to
the develop branch.
Updated to compile against the latest core
Merge pull request #97 from maksimov/develop

Updated to compile against the latest core
Merge pull request #96 from cafed00d/develop

Avoid NPE if no image class provided in filter options.
Moved in performance changes to MIs