refs #8371. Refactor toLam code. Method too large.

Better to break this function up into its monitor and detector components.
refs #8371. Transmission correction function added.

Basic transmission correction functionality. Will need refactoring as we go along. Only working for point detector mode with a single transmission workspace at the moment. No stitching yet.
refs #8371. Transmission correction with two corrections.

This involves using Stitch1D (currently a python algorithm). In order to do this I need to work around this interface a little by pushing the input workspaces into the ADS prior to algorithm execution, and cleaning them out again afterwards. When I move Stitch1D to be a c++ algorithm, I will no longer need to do this. More refactoring work is required around these new features.
refs #8371. Make StartOverlap and EndOverlap properties.

Previously these were hard-coded in the quick scripts, but it's very important that they are exposed.
Add checking and tests around these features. Refactoring step required to separate validation from setting of these optional parameters.
refs #8371. Intermediate refactoring.

Refactoring before I start tackling the rest of the multi-detector options, and IvsQ aspects of the conversion. Improve the documentation and make the methods const where possible.