Summary:
This diff changes the toplevel 'infer' executable from the current
python script to an OCaml binary. Currently this executable only parses
command line arguments, sets up environment variables, and invokes the
existing python script. This improves infer's command-line and
configuration interface, since passing arguments to the frontends or
backend no longer requires manually setting environment variables, and
arguments for the toplevel can now also be specified in .inferconfig.
Simplification and migration of functionality from the python script is
left for the future.
Reviewed By: martinoluca, jvillard
Differential Revision: D3450662
fbshipit-source-id: 1b52302