Fix issue #112, NPE in RocketFigure3d mouseDragged()
The component can pick up a mouse drag event without a mouse press event
if the mous is clicked and dragged while a modal dialog is open. The
running simulations progress bar dialog is an example. To fix, do not
process a mouse drag if a mouse press has not been recorded.
Fix for Issue #122, NPE in RocketFigure3d.setType()
This problem will only happen when the RocketFigure3d is unable to
create a GL canvas. It sets the canvas to null, but not all code that
uses canvas checks for null. This class probably should handle this
state better than it does, but this is the safe change now.
Updated thrustcurves.
Merge pull request #127 from openrocket/thrustcurves

Updated thrustcurves.
Merge remote-tracking branch 'upstream/master'