Update QuantumProgram.set_api() and add a new set_api_hubs_config()
method for being able to pass hub, group and project parameters to the
API, and modify it.
* Add runtime check for IBMQuantumExperience version
Add `qiskit._util._check_ibmqe_version()` (invoked on the main import)
for emitting a warning if the installed version of IBMQuantumExperience
does not match the version defined on `setup.py`.
* Rename requires.txt and requires-dev.txt
Rename to "requirements.txt" and "requirements-dev.txt", in order to
conform better to the de-facto practices.
Update the requirements to match the versions specified in setup.py.
* setup.py: OS classifiers, backend, IBMQE version
* Explicitly require IBMQuantumExperience>=1.8.13, as older versions
might not contain all the functionality needed.
* Include "qiskit.backends" as a package instead of "qiskit.simulators".
* Add trove classifiers for the operative systems supported.
* Fix PEP8 warnings for long description.
* Avoid using __version__ in setup.py due to imports
Revert the change of using "__version__" imported from "__init__.py"
directly on "setup.py", as the current importing of the modules from
"__init__.py" causes the building to fail due to the dependencies not
being available at the time of invocation.
Diego M. Rodriguez