WIP: improving support for ZLIB and adding Python wrapper

[jtrmal]

the python wrapper won't build under windows (cython generates code needing unistd.h and getpid())

[jtrmal]

I marked it as WIP, because I want to compile under Linux (or mac), just to make sure the cmake config is compatible enough

[kkm000]

@jtrmal, sure, feel free to merge or ping me if you want me to review (but I can hardly be of much help with CMake scripts).

[kkm000]

@jtrmal, when you're back and have time, we should probably finish this?

[kkm000]

@jtrmal, do you want to keep this open? Anything changed with later versions? Looks like it's seriously out of date.

[jtrmal]

yeah, let me put it on my todo and try to finish it