Do not stomp on existing cols, fixes #510.
Do not stomp on existing cols, fixes #510.

wenxer/peewee,bopo/peewee,jnovinger/peewee,softside/peewee,coreos/peewee,zhang625272514/peewee,wenxer/peewee,jarrahwu/peewee,coleifer/peewee,Dipsomaniac/peewee,jarrahwu/peewee,new-xiaji/peewee,bopo/peewee,coreos/peewee,jnovinger/peewee,ronyb29/peewee,jarrahwu/peewee,Sunzhifeng/peewee,new-xiaji/peewee,fuzeman/peewee,stas/peewee,Dipsomaniac/peewee,zhang625272514/peewee,teserak/peewee,fuzeman/peewee,Dipsomaniac/peewee,lez/peewee,coleifer/peewee,mackjoner/peewee,coreos/peewee,bopo/peewee,coleifer/peewee,new-xiaji/peewee,Sunzhifeng/peewee,ghukill/peewee,py4a/peewee,zhang625272514/peewee,Sunzhifeng/peewee