minor bugfix in PC chomping in flatten_header
minor bugfix in PC chomping in flatten_header

bsipocz/pyspeckit,vlas-sokolov/pyspeckit,e-koch/pyspeckit,vlas-sokolov/pyspeckit,jpinedaf/pyspeckit,keflavich/pyspeckit-obsolete,jpinedaf/pyspeckit,keflavich/pyspeckit,bsipocz/pyspeckit,allisony/pyspeckit,allisony/pyspeckit,e-koch/pyspeckit,keflavich/pyspeckit,low-sky/pyspeckit,mikelum/pyspeckit,low-sky/pyspeckit,pyspeckit/pyspeckit,pyspeckit/pyspeckit,dinossimpson/pyspeckit,dinossimpson/pyspeckit,mikelum/pyspeckit