Merge pull request #322 from shaitan/lts

Monitor: Added ability to extend monitor statistics via custom statistics providers.
tests: set stdout to sys.stdout instead of PIPE

It makes better user experience as tests' progress is printing
in real time
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
Merge pull request #324 from euroelessar/lts

prepare_latest fix
v2.24.15.1