Use pybind11 as binding framework

This commit changes the api for the Schedule class, the various time related
methods now return datetime.datetime instances instead of datetime.data.

python/CMakeLists.txt

@@ -1,11 +1,7 @@
 include( FindPythonModule )
 include( PythonPackage )
 
-#python_module( ctypes )
-python_module( six    )
-#python_module( numpy  REQUIRED 1.7  )
 python_module( inspect    OPTIONAL  )
-
 if (DEFINED PY_inspect)
   message(STATUS "We have inspect.")
 else()