Added preparation for GPU hardware accelerated solvers for BulletSoftBody (OpenCL and DirectCompute backends will follow)

Added assert to check for positive masses in btCompoundShape::calculatePrincipalAxisTransform, see Issue 399
Fixes for LLVM/GCC compilation issue in btSequentialImpulseConstraintSolver
(Untested) fix for Linux 64bit compilation Issue 409

src/LinearMath/btAlignedObjectArray.h

@@ -459,6 +459,13 @@ class btAlignedObjectArray
 		m_capacity = capacity;
 	}
 
+	void copyFromArray(const btAlignedObjectArray& otherArray)
+	{
+		int otherSize = otherArray.size();
+		resize (otherSize);
+		otherArray.copy(0, otherSize, m_data);
+	}
+
 };
 
 #endif //BT_OBJECT_ARRAY__