branch phoebe_legacy as phoebe1 backend of phoebe 2.0

[horvatm]

The branch "phoebe_legacy" contains the non-GUI part of phoebe1 into self-contained module (containing code and data) with the backend routines in C or Fortran compiled using (numpy).distutils.

It loads all PhoebeMethods with

import phoebe_legacy

Now somebody needs to

• write a small interface connecting existing routines with the module's data and by that make is independent of config files
• make a small cleanup of libphoebe_legacy.c. as we don't need lex code
• check the setup_*.py scripts and make it as general as possible.

After that the module is ready for use as an alternative backend in Phoebe 2.0 and can be compiled on any architecture that has a C and Fortran compiler and python distribution.

Actually we can try to make a f2c version of libwd, so that only C compiler is necessary and than phoebe2.0 can installed on almost arbitrary machine. This shouldn't be very difficult.

[horvatm]

phoebe_legacy as phoebe 1 interface works fine in all branches, as indicated by travis.