Revert to old time management (#1351)

As many users reported some problems with new time management,
and recent tests on longer time controls

http://tests.stockfishchess.org/tests/view/5a460e160ebc590ccbb8c35d
http://tests.stockfishchess.org/tests/view/5a462f4d0ebc590ccbb8c37a

are even little in favor of old time management, this revert seems as a logical step.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 14060 W: 2562 L: 2430 D: 9068

LTC:
LLR: 3.44 (-2.94,2.94) [-3.00,1.00]
Total: 31611 W: 3958 L: 3827 D: 23826

bench: 5365777 (same as master)