The non-linear least squares solver had the ability to update the
user's parameters every iteration. Now GradientProblemSolver can
do the same.
Also a few minor Sphinx markup related cleanup to the documentation
which were found in the process of updating Sphinx on my machine
and adding the docs for this feature.
This fixes https://github.com/ceres-solver/ceres-solver/issues/246
Change-Id: Ib6b90ac22be8bfb60b14f25ad52082ba371af164
1. Complete restructuring of the documentation to account for
GradientProblemSolver.
2. Update the version history to account for changes since 1.9.0.
3. Add links and document the various examples that ship with ceres.
4. Documentation for GradientProblem GradientProblemSolver.
Change-Id: If3a18f2850cbc98be1bc34435e9ea468785b8b27