prepare_latest fix

In case if one of prepare_latest's groups is not presented in
state's list prepare_latest throws an exception. This fix adds try
catch statement to catch the exception and returns appropriate
error code
v2.24.15.1
test: Don't use inline if/else syntax

Looks like python-2.6 doesn't understand it
tests: fixed pyton indent
tests: fixed python formatting
Monitor: Made elliptics_monitor as shared library.
Monitor: fixed losing elliptics_monitor.so via making elliptics_monitor static library with -fPIC. Python: downgraded checking python objec on None for boost 1.40 which doesn't support is_none() method.
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.