Problem: cffi bindings are slow to import and require C parser
Problem: cffi bindings are slow to import and require C parser

Solution: reorganize a concept totally. Those are changes
 * create Python package $(project.name)_cffi
 * move definitions to one file
 * add dlopen module for older approach
 * add build.py to actually build extension module
 * let __init__.py try native and fallback to dlopen version

Tested on czmq_cffi bindings

zeromq/zproject,zeromq/zproject,paddor/zproject,zeromq/zproject,paddor/zproject,paddor/zproject