cmd: detect code built in $PROJECT/src
cmd: detect code built in $PROJECT/src

Fixes #46

inconshreveable/gb,tianon/gb,hyper-carrot/gb,mopemope/gb,mopemope/gb,ches/gb,constabulary/gb,inconshreveable/gb,Luit/gb,constabulary/gb,davidkaya/gb,MerlinDMC/gb,hyper-carrot/gb,davidkaya/gb,ches/gb,guiquanz/gb,tbruyelle/gb,acasajus/gb,URXtech/gb,lparkes/gb,tianon/gb,tbruyelle/gb,constabulary/gb,mopemope/gb