mick-wright/Gravelamps: 2.0

Mass overhaul to the interface, based on suggestion by Isaac Wong:

• bilby_pipe functions more directly integrated within Gravelamps
• gravelamps.inference deprecated in favour of gravelamps.core with most utility functions residing within submodules here.
• pipe and local varieties of programs deprecated. Single gravelamps_inference and gravelamps_generate_lens programs now have local flag.
• Proper logging has been set up within the gravelog submodule using a logger from python builtin logging.
• Argument parsing via argparse set up within the programs (contained within gravelamps.core.graveparser).
• Documentation has been written about each of the programs and about the construction of the Gravelamps INI --- the format of which has been overhauled.
• C++ backend for the lensing modules has been overhauled; running of the lens generation now entirely done within the python code, directly calling the C++ as a backend as opposed to running a separate program.
• Ability to submit condor directly from programs has been added as flag.