Add capability to handle Path/LocalPath objects
fixes #11033

ok, looks reasonable

the `pathlib` test should pass on 3.4 and skip on all others (pls confirm via the travis log)
however, pls add `py` to the requirements-2.7.txt so conda will install it (so it will test)
 Docs would be great as well, in the docstring and in the `doc/source/io.rst`.
 can you add `pathlib` to one of the py2 builds 
pls add a whatsnew note for 0.17.1
 all done!
 anaconda can’t install pathlib. wat do?
 add to `ci/requirements-2.7.pip`
 pls squash. otherwise lgtm.
 squashed :+1: 
 done, sorry for the holdup
 merged via https://github.com/pydata/pandas/commit/82f0033369f417d0234990578c666947c50ee211

thanks!
 :fireworks: yeah!
