Uglify files one-to-one with their source as per the Play 2.2 behaviour. It makes sense given that we have no understanding of the order of js files required to be concatenated; thus we should let that be the concern of another pipeline stage task.

In addition we exclude uglifying any library files e.g. those from WebJars and the public folder.
Merge pull request #1 from huntc/single-file-compression

We should be able to minify file by file