Update README.md with release 1.5 information.
Update README.md with release 1.5 information.

frakc/DraggablePanel,murat8505/DraggablePanel,dfodor/DraggablePanel,Fiddl3/DraggablePanel,SPBTV/DraggablePanel,hmit/DraggablePanel,hoangsondev/DraggablePanel,ppamorim/DraggablePanel,pedrovgs/DraggablePanel,qiwx2012/DraggablePanel,Thornith/DraggablePanel,FreeDao/DraggablePanel