Updated to move attenuation to instrument definition file.

Refs #4841
Updated OSIRIS and IRIS parameter files.

Refs #4841
Implemented removing peaks.  Refs #7652.
Cleaned the code.  Refs #7652.
Added class NeutronBk2BkExpConvPVoigt.  Refs #7653.
Refactor codes.  Refs #7653.

Moved some methods belonged to ThermalNeutronBk2BkExpConvPVoigt to
IPowderDiffPeakFunction because they are used by
NeutronBk2BkExpConvPVoigt, too.
Checkpointing work.  Refs #7653.
Re #7701 Add transmission as output
Re #7701 Fix transmission workspace name in frame skipping mode
Checkpointing work.  Refs #7653.
Adding add sample log to Elwin

Refs #7711
Moved some common function to interface.  Refs #7653.
Complete coding (almost).  Refs #7653.
Refactor E1() to interface.  Refs #7653.
Checkpointing work. Refs #7653.
Fixed a bug during testing this ticket.  Refs #7653.
Added some unit test (incomplete).  Refs #7653.
Checkpointing work.  Refs #7653.
Merge branch 'master' into feature/7653_add_fp_peak9
Added some unit tests.  Refs #7653.