Cython rewrite and API update

Removed SWIG as the glue code generator and moved to Cython, which works like a dream. There is a new API which doesn't require the length of the list, and a compatibility call which follows the old call signature so that no client code breaks.

slatkin-exact-tools

v1.2

fixed build from make

slatkin-exact-tools

1.1

Adding -lm which is necessary on Linux

slatkin-exact-tools

1.0

Updated makefile - probably better way to install this than pip