ENH: Cleaned up the command line option wording.  Also added the prior probability weight when initializing with prior proabaility image(s).
ENH: Cleaned up the command line option wording.  Also added the prior probability weight when initializing with prior proabaility image(s).

DaisukeMiyamoto/ANTs,stnava/ANTs,dawnsong/ANTs,fliem/ANTs,DaisukeMiyamoto/ANTs,DaisukeMiyamoto/ANTs,fliem/ANTs,fbudin69500/ANTs,fbudin69500/ANTs,dawnsong/ANTs,stnava/ANTs,fliem/ANTs,fbudin69500/ANTs,stnava/ANTs,acaprihan/Lungs,acaprihan/Lungs,acaprihan/Lungs,fbudin69500/ANTs,fliem/ANTs,stnava/ANTs,stnava/ANTs,fbudin69500/ANTs,stnava/ANTs,acaprihan/Lungs,fliem/ANTs,fliem/ANTs,fbudin69500/ANTs,dawnsong/ANTs,fliem/ANTs,dawnsong/ANTs,DaisukeMiyamoto/ANTs,DaisukeMiyamoto/ANTs,DaisukeMiyamoto/ANTs,stnava/ANTs,dawnsong/ANTs,acaprihan/Lungs,fbudin69500/ANTs,acaprihan/Lungs,DaisukeMiyamoto/ANTs,dawnsong/ANTs,dawnsong/ANTs