Minor:
- xbcomponent: 
	- moved definition of applied forces from __init__ method to allow them to be used as design parameters in OpenMDAO
	- added few options to use rectangular loads
- commented writing results for rigid body + structural dynamics simulation in Fortran code
- added method to create rectangular input force
- updated lib.read, lib.save to read/save to h5 the output from rigid body + str. dynamics simultion