Fixed #495; made removal of the only start block impossible (#502)
Fixed #495; made removal of the only start block impossible (#502)

* Fixed #495; made removal of the only start block impossible

* Changed error message when removing last start block

walterbender/musicblocks,Hrishi1999/musicblocks,sachi-d/musicblocks,Hrishi1999/musicblocks,sachi-d/musicblocks,eohomegrownapps/musicblocks,eohomegrownapps/musicblocks,Hrishi1999/musicblocks,sachi-d/musicblocks,walterbender/musicblocks,eohomegrownapps/musicblocks,walterbender/musicblocks