Use verbose output and counter

Implements #97 -

Listing every file it processes can be quite a lot of spam, so changing it to use grunt.verbose.writeln instead of grunt.log.writeln would make it nicer to use (keeping the warnings as they are etc). Basically this makes a huge difference on windows where the log size is severely restricted.

Additionally adding a log (not verbose) count after finishing would keep people informed how things went.