Fix instability in getProjectSize & getProjectExtent,increased the timeline bounds to 99999

The code getProjectSize and getProjectExtent would start to hand back incorrect/corrupt frame sizes when processing a long clip. By changing from getFirstData to getData( _dataAtTime.size()-1 ) the values return remain stable.

The effect duration and timeline bounds where changed from 25 to 99999 as having such a low figure caused problems with effects that processed more than 25 frames.