Skeleton for building a Cython module

This breaks the solver until some of the core classes have Cython interfaces.
Updated build scripts so that Cython build works on Windows
Build the Python module in build/python/ember

This makes 'build/python' suitable for adding to the PYTHONPATH
Changes to C++ source files trigger Python rebuild
Changes to Python and Cython files triggers appropriate rebuilds
Implemented the Cython ConfigOptions class
Implemented the Cython FlameSolver class

This is sufficient for running from the command line using the Cython interface.
Made basic solver state and integral properties available in Python
Fixed the GUI to work with the Cython module
Removed code for the Boost.Python module
Removed the no-longer-used Boost.NumPy library from ext/
Updated paths and dependencies in README.rst
Fixed compatibility with Python 2.6