Algorithm for fixing negative values in data

[Peter Peterson]

There are two behaviors to this:

1. Convert negative y-values to a defined value (default is zero)
2. Add a constant to each spectrum based on its minimum value being negative (i.e. if the minimum is -100, add 100 to that spectrum).

[Peter Peterson]

Refs #4711. Adding new class to reset negative values to something gsas will like.

Refs #4711. Adding initial class.

Refs #4711. It works for the first test case.

Refs #4711. Adding unit tests.

Refs #4711. Adding doxygen comments.

Refs #4711. Adding user docs and progress bar.

Refs #4711. -0. is now converted to 0.

Changeset: c054c88a9f29d386ac1f1ef6b396f3e7a0f7694f

[Peter Peterson]

Refs #4711. Using ResetNegatives.

Changeset: fbe4ba04632a0733f14c1f8739779dd1ff77f668

[Peter Peterson]

Refs #4711. Fixing broken test.

Changeset: 76cb24fb8849e7976ddf5d10b9c2ac11e3e0806d

[Stuart Campbell]

This ticket has been transferred to github issue ​5558