Refactor ComptonScattering to allow for a background.

The constraint matrices need to expand if a background is to be
included.
Refs #7492
Allow ComptonScatteringCountRate to include a background.

Refs #7492
Alter ComptonProfile to require input data in seconds.

Avoids having to implement custom background functions that understand
that the data must be in seconds.
Refs #7492
Added AugmentedLagrangianOptimizer

Used for solving minimization problems subject to constraints.
Refs #7492
Use AugmentedLagrangian optimizer in ComptonScatterCountRate

It is better at dealing with larger scale objective functions when the
background is included.
Refs #7492
Merge remote-tracking branch 'origin/feature/7492_background_in_compton_scattering'