Added an instance of CoordinateSystem to the class SlipPlane.
Added coordinatesystem updating function calls in
simulateSingleSlipPlane functions.
Added function getCoordinateSystem
This function returns a pointer to the slip plane's coordinate system.
This will be useful for assigning the base pointers for coordinate
systems of all entities lying on this slip plane.
Corrected error in Peach-Koehler force expression.
Merge pull request #12 from adhishm/version_0.0_simulateSingleSlipPlane_StrongInheritance_CorrectPeachKoehler

Version 0.0 simulate single slip plane strong inheritance correct peach koehler