Warn about missing targets when task "options" exists. Closes gh-1042.
Warn about missing targets when task "options" exists. Closes gh-1042.

thecc4re/gruntjs,paulcbetts/grunt,paladox/grunt,vladikoff/grunt,yonglehou/grunt,r14r-work/fork_grunt_master,JaKXz/grunt,eelve/grunt,modulexcite/grunt,youmyyou/grunt,thejameskyle/grunt,coldrye-collaboration/grunt,goodeggs/grunt,fscherwi/grunt,yosiazwan/grunt,yuhualingfeng/grunt,zackexplosion/grunt,abraheem/grunt,q310550690/grunt,r14r/fork_grunt_master,IveWong/grunt,ThiagoGarciaAlves/grunt,imjerrybao/grunt,arosa81/grunt,felixgrey/grunt,FeodorFitsner/grunt,Chhunlong/grunt,pandeysoni/grunt,lkiarest/grunt,shama/grunt