Add Makefile which wraps build and upload commands
Add Makefile which wraps build and upload commands

Also has an important `make help` to help people figure out what to do
with the Makefile. Supports a local dev setup, building package
versions, uploading to pypi, building docs, running tests, and the
omnipresent "clean".
Also has an "all" target to try to lead people to success.
Default target is help.

aaschaer/globus-sdk-python,globus/globus-sdk-python,globus/globus-sdk-python,globusonline/globus-sdk-python,sirosen/globus-sdk-python