Automatic Differentiation 'Dual' Type (#100)

* Dual numbers initial implementation

* Add test coverage, with partial derivative example

* Add Jacobian test, fix small issues

* Improve test to demonstrate non-square jacobian

* Better naming for collectReals/Derivatives

* Improve comments

* Potential GCC 4.8 bug workaround

* Add fallback workaround for non-IEEE float platforms

matrix/math.hpp

@@ -17,3 +17,4 @@
 #include "Quaternion.hpp"
 #include "AxisAngle.hpp"
 #include "LeastSquaresSolver.hpp"
+#include "Dual.hpp"