Add "rename folder" to first step

I downloaded the zip from the website and it was named `craft-scrawl-master`. I moved it to the plugins folder and it wasn't showing up. The first thing I did was rename it to just `scrawl`, then everything was cool. But, I think that renaming it shouldn't be implied.
Merge pull request #1 from james2doyle/patch-1

Add "rename folder" to first step