Allow erlang ad-hoc functions in m/r (allow_strfun)
Merge branch 'master' of https://github.com/wamdam/riak-python-client into pevm-wamdam-strfun
add a test & try to catch when allow_strfun is false
narrow the scope of the catch so that fewer errors are masked,
append the original error for user evaluation.

this still masks typos in the strfun code, because they're
indistinguishable from the strfun not allowed message,
and it's impossible to tell, client side, which is which.
Merge pull request #211 from basho/pevm-wamdam-strfun

Allow erlang functions to be passed as strings