yet another python extension to channel access

[Xiaoqiang Wang <xiaoqiang.wang@psi.ch>]

Hi,

As usual, it is started as a learning project and then made functional.
When compared to other implementations, it differs in the following:
  * Use cffi[1]. This reduces the extra data structure declarations compared to the solution based on ctypes. see [2] for a simple comparison. Compared to Python C/API and SWIG, it does not involve any C programming.
  * Provide only low level, one-to-one mapping of ca_xxx functions. But data types conversion are being handled.

As being primitive, it serves as basis to build high level interfaces. A re-implementation of the CaChannel interface is shipped within the package.

Its homepage is https://pypi.python.org/pypi/caffi


Best
Xiaoqiang

[1] https://pypi.python.org/pypi/cffi
[2] http://eli.thegreenplace.net/2013/03/09/python-ffi-with-ctypes-and-cffi/