Show detectors now shows Q value.

Refs #7729
Refactoring and tidying up.

Refs #7729
Removed unused local variable.

Refs #7729
Swapped out using ConvertSpectrumAxis algorithm for just the raw calculations.

This should make calculation of Q a little more lightweight.

Refs #7729
Added better output for when there is no EFixed value.

Refs #7729
Changed to better method of finding Efixed value.

Refs #7729
Created ElasticQ conversion function.

Refs #7729
A little refactoring to tidy up.

Refs #7729
Merge remote-tracking branch 'origin/feature/7729_q_val_in_show_detectors'