Simulate Single Rail Button Flight Phase

[giovaniceotto]

The current Flight simulation does not take into account the fact the for a very short amount of time, a high powered rocket is guided through the launch rail with a single rail button, after the first has already cleared the rail. Under this condition, the rocket displays a planar motion, with 3 degrees of freedom.

This should be implemented as a new flight phase due to its importance to dynamic stability when the rocket is clearing the rail.

[giovaniceotto]

Working on it in the rail_buttons branch.