EHN: Allow load_data to load problematic R datasets
TST: Move tests from rpy/common.py to tests/test_rpy.py
TST: Add tests to demonstrate the enhancements made to rpy/common.py.
DOC: Add explanation to doc/source/release.rst

This is related to #5036, which I unwittingly closed while trying to clean up my commit history.
 @unutbu looks fine...and since you are the one to test it, good to go?
 actually....do you want to put a mention (maybe code-block example?) in v0.13.0?
 Yes, I think it is good to go.
 (Assuming the change to v.0.13.0.txt is acceptable).
 @unutbu can you move the test file into a subdirectory of rpy?
so it would go into `rpy/tests/<your_filename_here>.py`
 ready to go on this?
 Need to add init file to test folder, right? (maybe I'm just missing it) 
 I hope this isn't too many commits. If so, I could delete this branch and start a new one with a shorter history. Please tell me if there is a better way.
 can u rebase and squash?

no need to delete 

https://github.com/pydata/pandas/wiki/Using-Git
 @jtratner @cpcloud merge?
 let me test this out
 needs a rebase ... there's probably a merge conflict with release or v0.13.0.txt
 looks good on my end ... merge conflicts in the two files mentioned ... @unutbu just rebase and good 2 go
 thank you
 No, thank you. That was fun!
