fix cases where request.response would evaluate to false, and we'd erroneously enter the exception handling code
request.response is init'd to None, so the more appropriate test is the 'is not None' comparison.
stuff the traceback from the exception into the AsyncRequest object as well
bump version number to 0.3.0
don't try to call the exception handler if it isn't set
add test to illustrate @agsimeonov's digression from 0.2.0 in map response
map: restore 0.2.0 behavior for cases with no exception handler; allow the exception handler to determine what, if anything, gets put in the result list
enhance the tests a little bit, make sure None/returned value is set correctly
tests: starting imap tests, further refinement to map tests
tests: imap test for exception handler returns value
map: output array length will always match input length.
docs: updated
Merge branch 'exceptions' into 0.3.0
bump version to 0.3.1
Merge from #58!