-Implemented support for LIVE SYNC testing including mock processing while...

-Implemented support for LIVE SYNC testing including mock processing while passed test_max_block value is higher than last irreversible block provided by hived node.
-Also when test_max_block option is passed, StaleHeadBlock check is not performed, since tested head block is far away from current real time.
-Removed option exit-after-sync
-Eliminated strange block popping from mock provider implementation.
-Eliminated linear complexity to estimate a max head block provided by mock implementation