Add Omnibus::Project#dependency DSL method
Add Omnibus::Project#dependency DSL method

This cleans up the DSL a bit by allowing the specification of
build-time dependencies one-at-a-time.

rhass/omnibus,ashhher3/omnibus,intfrr/omnibus,hugosato/omnibus,3ofcoins/chef-omnibus,adamleff/omnibus,lvfeng1130/omnibus,higanworks/omnibus,DataDog/omnibus-ruby,Altiscale/omnibus,pskrz/omnibus,jamesn/omnibus,jamesn/omnibus,Altiscale/omnibus,sh9189/omnibus,mattray/omnibus,intfrr/omnibus,strangelittlemonkey/omnibus,strangelittlemonkey/omnibus,strangelittlemonkey/omnibus,higanworks/omnibus,rapid7/omnibus,higanworks/omnibus,chef/omnibus,rhass/omnibus,pskrz/omnibus,3ofcoins/chef-omnibus,szechyjs/omnibus,servebox/omnibus,chef/omnibus,pskrz/omnibus,hugosato/omnibus,szechyjs/omnibus,sh9189/omnibus,DataDog/omnibus-ruby,szechyjs/omnibus,jamesn/omnibus,DataDog/omnibus-ruby,servebox/omnibus,lvfeng1130/omnibus,rapid7/omnibus,mattray/omnibus,Altiscale/omnibus,ashhher3/omnibus,rhass/omnibus,adamleff/omnibus,Scalr/omnibus,lvfeng1130/omnibus,intfrr/omnibus,chef/omnibus,ashhher3/omnibus,rapid7/omnibus,sh9189/omnibus,mattray/omnibus,3ofcoins/chef-omnibus,hugosato/omnibus,Scalr/omnibus,adamleff/omnibus,servebox/omnibus,Scalr/omnibus