GenericChecksumRewriter no longer adds checksums to images

  * Updated ImageObjectRenderer to introduce the checksum
Separating struts from the renderers core
Removing deprecated JDom dependency
Cleanup
Cleaning up renderers internals
More cleanup
More cleanup
Unified ViewState params
Even more clenaup
Removed redundant taglibs
RenderMode is now an enum
Removed needless cache
Don't use Hashtables
Removed schema registry
Renderers now generate Bootstrap-compatible markup