Merge pull request #333 from shaitan/lts

Monitor: Added REST-like api for getting monitor statistics.
Python: fixed None usage as Id in session.exec_()

Check must directly compare PyObject* to Py_None singleton, because other method
(checking object equality to python::api::object()) involves user defined
comparing/equality operators.
This is the case with elliptics.Id which has __cmp__ method, which
cannot accept None as an argument.
Merge pull request #336 from ijon/lts

Python: fixed None usage as Id in session.exec_()
Python: fixed writting out of memory.