Fix rounding error in msvQTimePlayerWidget

When the range was 5.0, the number of steps 6, timeToFrame failed to
return 3 when time is 3.0. It was casting 2.99999999 in 2
Cleanup msvQTimePlayerWidget

* Rename lastTimeRequest into currentTime
* cleanup frameToTime() and timeToFrame()
Add tooltips to msvQTimePlayerWidget

Closes #1
Merge branch 'msvQTimePlayerWidget'

* msvQTimePlayerWidget:
  Add tooltips to msvQTimePlayerWidget
  Cleanup msvQTimePlayerWidget
  Fix rounding error in msvQTimePlayerWidget