Reimplemented cEvent using C++11 primitives.

Fixes #1523.
Merge branch 'master' into c++11Events
Added a missing chrono include.
Moved the chrono include into Globals.
Merge branch 'master' into c++11Events
cEvent: Changed steady_clock to system_clock.
cEvent: Changed chrono duration resolution.
Merge remote-tracking branch 'origin/master' into c++11Events
Fixed integer overflow problems.

The event would overflow when requesting a 60 minute timeout.
cMojangAPI: Fixed a possible problem with thread termination order.
Merge pull request #1563 from mc-server/c++11Events

Reimplemented cEvent using C++11 primitives.