Bug/156/exciter bpms
Created by: lmalina
Added exciter BPMs (closest to AC-dipoles) for PS and PSBooster - fixes #156 (closed) Added simple model creation tests for PS and PSBooster model creation test reflect what is the needed pre-processing (i.e. modifiers.madx file) Changed the classmethods in LHC acelerator class - fixes #159 (closed)