Autodiff local parameterization class

This class is used to create local parameterization
with Jacobians computed via automatic differentiation.

To get an auto differentiated local parameterization,
class with a templated operator() (a functor) that
computes

 plus_delta = Plus(x, delta);

shall be defined.

Then given such functor, the auto differentiated local
parameterization can be constructed as

 LocalParameterization* local_parameterization =
   new AutoDiffLocalParameterization<PlusFunctor, 4, 3>;
                                                  |  |
                       Global Size ---------------+  |
                       Local Size -------------------+

See autodiff_local_parameterization.h for more information
and usage example.

Initial implementation by Keir Mierle, finished by self
and integrated into Ceres and covered with unit tests
by Sameer Agarwal.

Change-Id: I1b3e48ae89f81e0cf1f51416c5696e18223f4b21
4 files changed