Unify naming rule.
Implement scalable clock.
Refactor the clock module.
Fix an exception when importing.
Fix an overflow issue.
Implement pausable clock.
Fix an override issue.
Implement timer for game.
Update VS project file.
Fix some bugs of timer.
Modify the looping counter of timer.
Fix compilation error in GCC.
Merge pull request #3 from layzerar/dev

Merge from development brance.