Floating time step in flight simulation

**Requirement Text**
UAV model shall be able to simulate forward at any reasonable dt 

**Background Information**
Right now the flight model requires that you use a set dt- that used to make the waypoints.

**Suggested Solution**
Interpolate if between points

**DoD**
 - [ ] Implement feature
 - [ ] Add to example 
 - [ ] Add tests 
 - [ ] update documentation for feature