CalibrateRectangularDetectors on SNAP

[Peter Peterson]

The multi-peaks option doesn't work for two reasons:

1. SumNeighbors accidentally finds a monitor as a regular detector so doesn't use the rectangular detectors option
2. CalibrateRectangularDetectors has some special branches for SNAP which are no longer necessary. Remove them other than the special case when loading prenexus files.

[Peter Peterson]

Re #7799. Setting the second monitor as a monitor on SNAP.

Changeset: 4520dbfc510ba1ec67851eb34ae2e9987ca475db

[Peter Peterson]

Re #7799. Removing SNAP specific branches from CalibrateRectDetectors.

Changeset: efdd33a85ad4f58e74c52e040679df525f7434e7

[Peter Peterson]

This is on ​bugfix/7799_snap_calibration.

To test:

1. Look at the new version of the SNAP geometry file.
2. Run CalibrateRectangularDetectors with SNAP_12696, and sumx=64, sumy=64, and peak positions of .8258,.9046,1.0113,1.1678,1.4303,2.0227 and DiffractionFocus the result turned on. This shouldn't take forever to run and should give reasonable peaks.

[Vickie Lynch]

Calibration looks good and took only 43 seconds. PG3 calibration still works.

[Stuart Campbell]

This ticket has been transferred to github issue ​8644