get_changed_studies method added
one more test to verify the behavior on bogus SHAs
Just logging a message of cache failure

No longer logging the exception. This failure is expected
if you are not running redis to cache.
some tests commented out
reinstating full set of tests
Merge branch 'master' into issue-11
using correct repo name for phylesystem-api
Merge pull request #41 from OpenTreeOfLife/issue-38

Issue 38 'report study IDs that have changed between 2 branches/commits' ... and command line nexson conversion, etc.
Merge tests
Merge commit - #11
Merge pull request #56 from OpenTreeOfLife/pip-installable

Pip installable
Merge pull request #57 from OpenTreeOfLife/merge-fix

bug fix in code for merging OTU groups
conflict resolution
print is a function now...
bug fix in check for test skip. Thanks @jimallman
Merge pull request #58 from OpenTreeOfLife/py3

Py3
beginning of induced_tree method
resolved merge conflicts