Fix ps on Docker 0.8.1 when there is no command
Fix ps on Docker 0.8.1 when there is no command

Fixes #138

KevinGreene/compose,hoogenm/compose,joaofnfernandes/docker.github.io,shubheksha/docker.github.io,glogiotatidis/compose,jgrowl/compose,danix800/docker.github.io,phiroict/docker,ralphtheninja/compose,cgvarela/compose,amitsaha/compose,ionrock/compose,gtrdotmcs/compose,Yelp/docker-compose,screwgoth/compose,BSWANG/denverdino.github.io,dopry/compose,BSWANG/denverdino.github.io,MSakamaki/compose,docker/docker.github.io,uvgroovy/compose,sanscontext/docker.github.io,nhumrich/compose,anweiss/docker.github.io,TomasTomecek/compose,gdevillele/docker.github.io,denverdino/denverdino.github.io,j-fuentes/compose,artemkaint/compose,charleswhchan/compose,rillig/docker.github.io,ChrisChinchilla/compose,philwrenn/compose,DoubleMalt/compose,schmunk42/compose,menglingwei/denverdino.github.io,Katlean/fig,bfirsh/fig,vdemeester/compose,thaJeztah/docker.github.io,lmesz/compose,denverdino/compose,KevinGreene/compose,tpounds/compose,BSWANG/denverdino.github.io,goloveychuk/compose,mosquito/docker-compose,ZJaffee/compose,VinceBarresi/compose,cclauss/compose,iamluc/compose,TheDataShed/compose,nerro/compose,ph-One/compose,gdevillele/docker.github.io,dnephin/compose,tangkun75/compose,mark-adams/compose,rillig/docker.github.io,GM-Alex/compose,shubheksha/docker.github.io,rgbkrk/compose,shin-/docker.github.io,feelobot/compose,joaofnfernandes/docker.github.io,mindaugasrukas/compose,noironetworks/compose,JimGalasyn/docker.github.io,ZJaffee/compose,mchasal/compose,menglingwei/denverdino.github.io,talolard/compose,bcicen/fig,simonista/compose,aduermael/docker.github.io,rillig/docker.github.io,thaJeztah/docker.github.io,mnuessler/compose,ggtools/compose,prologic/compose,alexisbellido/docker.github.io,calou/compose,denverdino/denverdino.github.io,menglingwei/denverdino.github.io,jessekl/compose,lukemarsden/compose,jzwlqx/denverdino.github.io,sebglazebrook/compose,mchasal/compose,mrfuxi/compose,denverdino/docker.github.io,menglingwei/denverdino.github.io,thaJeztah/compose,josephpage/compose,mdaue/compose,LuisBosquez/docker.github.io,mark-adams/compose,jeanpralo/compose,gdevillele/docker.github.io,docker-zh/docker.github.io,gdevillele/docker.github.io,troy0820/docker.github.io,londoncalling/docker.github.io,jzwlqx/denverdino.github.io,ggtools/compose,ain/compose,londoncalling/docker.github.io,thaJeztah/docker.github.io,JimGalasyn/docker.github.io,vlajos/compose,bcicen/fig,noironetworks/compose,joaofnfernandes/docker.github.io,rstacruz/compose,andrewgee/compose,jrabbit/compose,jorgeLuizChaves/compose,saada/compose,viranch/compose,shin-/docker.github.io,abesto/fig,genki/compose,MSakamaki/compose,pspierce/compose,marcusmartins/compose,gtrdotmcs/compose,johnstep/docker.github.io,LuisBosquez/docker.github.io,bsmr-docker/compose,schmunk42/compose,Katlean/fig,anweiss/docker.github.io,BSWANG/denverdino.github.io,heroku/fig,talolard/compose,Dakno/compose,alexisbellido/docker.github.io,JimGalasyn/docker.github.io,au-phiware/compose,jonaseck2/compose,GM-Alex/compose,swoopla/compose,sanscontext/docker.github.io,alexandrev/compose,j-fuentes/compose,denverdino/compose,shubheksha/docker.github.io,sdurrheimer/compose,zhangspook/compose,d2bit/compose,ph-One/compose,kikkomep/compose,michael-k/docker-compose,calou/compose,rillig/docker.github.io,pspierce/compose,bdwill/docker.github.io,danix800/docker.github.io,alexandrev/compose,marcusmartins/compose,shubheksha/docker.github.io,mosquito/docker-compose,docker-zh/docker.github.io,viranch/compose,dbdd4us/compose,prologic/compose,twitherspoon/compose,abesto/fig,thaJeztah/docker.github.io,shin-/compose,feelobot/compose,LuisBosquez/docker.github.io,benhamill/compose,docker-zh/docker.github.io,JimGalasyn/docker.github.io,xydinesh/compose,jzwlqx/denverdino.github.io,dilgerma/compose,johnstep/docker.github.io,thieman/compose,mnuessler/compose,andrewgee/compose,dockerhn/compose,phiroict/docker,bdwill/docker.github.io,shin-/docker.github.io,joaofnfernandes/docker.github.io,bobphill/compose,ekristen/compose,cgvarela/compose,vdemeester/compose,troy0820/docker.github.io,philwrenn/compose,joeuo/docker.github.io,brunocascio/compose,TheDataShed/compose,glogiotatidis/compose,johnstep/docker.github.io,mnowster/compose,dilgerma/compose,twitherspoon/compose,funkyfuture/docker-compose,browning/compose,kojiromike/compose,runcom/compose,sanscontext/docker.github.io,londoncalling/docker.github.io,KalleDK/compose,jeanpralo/compose,alexisbellido/docker.github.io,londoncalling/docker.github.io,bdwill/docker.github.io,danix800/docker.github.io,brunocascio/compose,jiekechoo/compose,mohitsoni/compose,jrabbit/compose,bbirand/compose,thaJeztah/compose,browning/compose,unodba/compose,bbirand/compose,sdurrheimer/compose,thieman/compose,hypriot/compose,uvgroovy/compose,shubheksha/docker.github.io,denverdino/docker.github.io,mdaue/compose,johnstep/docker.github.io,dopry/compose,alexisbellido/docker.github.io,joeuo/docker.github.io,kikkomep/compose,BSWANG/denverdino.github.io,DoubleMalt/compose,KalleDK/compose,troy0820/docker.github.io,goloveychuk/compose,moxiegirl/compose,mnowster/compose,docker-zh/docker.github.io,sebglazebrook/compose,alunduil/fig,docker-zh/docker.github.io,vlajos/compose,joaofnfernandes/docker.github.io,saada/compose,michael-k/docker-compose,anweiss/docker.github.io,denverdino/docker.github.io,unodba/compose,qzio/compose,dockerhn/compose,alunduil/fig,cclauss/compose,benhamill/compose,phiroict/docker,dnephin/compose,ouziel-slama/compose,RobertNorthard/compose,menglingwei/denverdino.github.io,hypriot/compose,LuisBosquez/docker.github.io,shin-/docker.github.io,bcicen/fig,shakamunyi/fig,jgrowl/compose,heroku/fig,mindaugasrukas/compose,charleswhchan/compose,mbailey/compose,VinceBarresi/compose,bdwill/docker.github.io,iamluc/compose,londoncalling/docker.github.io,tiry/compose,au-phiware/compose,albers/compose,docker/docker.github.io,jessekl/compose,swoopla/compose,tpounds/compose,jiekechoo/compose,sanscontext/docker.github.io,aanand/fig,ain/compose,qzio/compose,anweiss/docker.github.io,shin-/docker.github.io,aanand/fig,troy0820/docker.github.io,bdwill/docker.github.io,jorgeLuizChaves/compose,jonaseck2/compose,aduermael/docker.github.io,joeuo/docker.github.io,danix800/docker.github.io,ChrisChinchilla/compose,aduermael/docker.github.io,docker/docker.github.io,amitsaha/compose,Yelp/docker-compose,johnstep/docker.github.io,alexisbellido/docker.github.io,kojiromike/compose,rgbkrk/compose,gdevillele/docker.github.io,phiroict/docker,ekristen/compose,docker/docker.github.io,shin-/compose,albers/compose,jzwlqx/denverdino.github.io,mrfuxi/compose,dbdd4us/compose,Chouser/compose,mohitsoni/compose,lmesz/compose,denverdino/docker.github.io,anweiss/docker.github.io,denverdino/denverdino.github.io,ionrock/compose,JimGalasyn/docker.github.io,Dakno/compose,xydinesh/compose,docker/docker.github.io,bsmr-docker/compose,TomasTomecek/compose,genki/compose,lukemarsden/compose,tiry/compose,nhumrich/compose,joeuo/docker.github.io,RobertNorthard/compose,runcom/compose,bfirsh/fig,LuisBosquez/docker.github.io,shakamunyi/fig,phiroict/docker,moxiegirl/compose,joeuo/docker.github.io,denverdino/docker.github.io,sanscontext/docker.github.io,hoogenm/compose,ralphtheninja/compose,jzwlqx/denverdino.github.io,d2bit/compose,Chouser/compose,aduermael/docker.github.io,denverdino/denverdino.github.io,ouziel-slama/compose,nerro/compose,thaJeztah/docker.github.io,rstacruz/compose,mbailey/compose,funkyfuture/docker-compose,bobphill/compose,zhangspook/compose,josephpage/compose,tangkun75/compose,denverdino/denverdino.github.io,screwgoth/compose,heroku/fig,simonista/compose,artemkaint/compose