Added ability to specify 'bonus' params.

* Model can provide bonus params, which are quantities computed
  from the model but not actually parameters.
* Improve some of the example codes, have them use printStatistics.
Merge branch 'base'

Conflicts:
	configure.ac
Add mean flux per unit area as bonus parameter for 1D model.

* Compiles, not tested.
Merge branch 'master' of https://github.com/aconley/pofd_affine