Stdin/out+foo.service() patch

Now handles stdin/stdout:
  ngmin f1 f2 -o out 
  cat *.js | ngmin | cat >out.js
Doesn't require angular.module().service(...) anymore, can also be fooApp.service(...)

Thanks for this neat tool. 

In the normal unix tradition, I added the option to add multiple files (output is now with -o) and also to process stdin and stdout.

Also, since a lot of projects don't use angular.module('foo',[]).service in each file, I changed the handling to foo.service(..)