Add convince mapping for selecting and display of common detector and pixel selections

[samaloney]

Add convince mapping for common detector and pixel selections to names and vice versa

Detector

name	meaning
'all'	all detectors
'imaging'	30 imaging detector (excluding BKG and CFL)
'imaging_24'	24 standard (not fine) imaging detectors
'imaging_fine'	6 finest imaging detectors
'cfl'	Only CLF detector
'bkg'	Only BKG detector

Pixel

name	meaning
'all'	All pixels (top, bottom and small)
'big'	All big pixel top + bot
'top'	Top row pixels only
'bottom'	Bottom row pixels only
'small'	Small, middle row pixels only