A description of the problem is found in https://developer.blender.org/T36425#19 .
The cause of the issue was identified as roudning errors in Operators::createStroke() due
to insufficient numerical precision. Precision promotion from float to double was done in
the return values of getPoint3D/2D methods in Interface0D and its subclasses in C++
(data members stored in the 0D classes have already been in double precision).
(See commit e1771e72fbbf828dbf5bed871b814288389f3611 for more detail of
the problem).
Made changes to intern/view_map/Interface0D.h and intern/python/Director.h to
avoid #include <Python.h> and keep non-Python header files independent of it.
