Big work-in-progress refactoring of the constraint solver:

1) Add fast branchless SIMD support for constraint solver (Windows only until we get other contributions).
See resolveSingleConstraintRowGenericSIMD in Bullet/src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
resolveSingleConstraintRowGenericSIMD can be used for all constraints, including contact, point 2 point, hinge, generic etc.

2) During this refactoring, all constraints support the obsolete 'solveConstraintObsolete' while we add 'getInfo1' and 'getInfo2' support.
This interface is almost identical interface to Open Dynamics Engine, to make it easier to port Dantzig LCP solver.

3) Some minor refactoring to reduce huge constructor overhead in math classes.

src/LinearMath/btQuadWord.h

@@ -24,13 +24,13 @@ subject to the following restrictions:
 #include <altivec.h>
 #endif
 
-/**@brief The btQuadWordStorage class is base class for btVector3 and btQuaternion. 
+/**@brief The btQuadWord class is base class for btVector3 and btQuaternion. 
  * Some issues under PS3 Linux with IBM 2.1 SDK, gcc compiler prevent from using aligned quadword.
  */
 #ifndef USE_LIBSPE2
-ATTRIBUTE_ALIGNED16(class) btQuadWordStorage
+ATTRIBUTE_ALIGNED16(class) btQuadWord
 #else
-class btQuadWordStorage
+class btQuadWord
 #endif
 {
 protected:
@@ -45,15 +45,11 @@ public:
 	{
 		return mVec128;
 	}
+protected:
 #else //__CELLOS_LV2__ __SPU__
 	btScalar	m_floats[4];
 #endif //__CELLOS_LV2__ __SPU__
 
-};
-
-/** @brief The btQuadWord is base-class for vectors, points */
-class	btQuadWord : public btQuadWordStorage
-{
 	public:
   
 
@@ -134,11 +130,7 @@ class	btQuadWord : public btQuadWordStorage
 		//	:m_floats[0](btScalar(0.)),m_floats[1](btScalar(0.)),m_floats[2](btScalar(0.)),m_floats[3](btScalar(0.))
 		{
 		}
-  /**@brief Copy constructor */
-		SIMD_FORCE_INLINE btQuadWord(const btQuadWordStorage& q)
-		{
-			*((btQuadWordStorage*)this) = q;
-		}
+ 
   /**@brief Three argument constructor (zeros w)
    * @param x Value of x
    * @param y Value of y