Added register_exception for nicely logging a given exception with all its contextual information. To be used as in: try:    raise InvenioFooException('this is a nice message') except InvenioFooException, e:    register_exception(req=req)
Added register_exception for nicely logging a given exception with all its
contextual information. To be used as in:
try:
   raise InvenioFooException('this is a nice message')
except InvenioFooException, e:
   register_exception(req=req)

It automatically discover the last caught exception.

tiborsimko/invenio,inveniosoftware/invenio,inveniosoftware/invenio,tiborsimko/invenio