Without the complete tracebacks it's fairly frustrating to try and track down the import errors.
Include traceback when reporting ImportErrors.
Note: I haven't yet tested the multiprocessing and jinja2 handlers. They look like they should work, though, and if this patch is going to be accepted I'll test them properly.
I actually think I do display the traceback for the multiprocessing import, for this very reason, but it looks like that was not considered for those other optional requirements. Good catch!
Pull in wolever traceback improvements for jinja2, paramiko
Add wolever's update for multiprocessing re #450