Update README for elm-package installation instructions.
Update README for elm-package installation instructions.

jlongster/dreamwriter,makyo/dreamwriter,Softsapiens/dreamwriter,Iced-Tea/dreamwriter,manesiotise/dreamwriter,rtfeldman/dreamwriter,zztczcx/dreamwriter,zztczcx/dreamwriter,rtfeldman/dreamwriter,Softsapiens/dreamwriter,manesiotise/dreamwriter,Iced-Tea/dreamwriter,makyo/dreamwriter,ajnsit/dreamwriter,ajnsit/dreamwriter,jlongster/dreamwriter