Add the cmd/args/cwd to the verbose output

[brianmhunt]

It would help quite a bit with debugging to output the cmd, args and cwd to the grunt verbose stream before the command is executed i.e. add before the grunt.util.spawn in tasks/external_daemon.js (around line 65) something akin to the following:

    grunt.verbose.writelns("cwd", process.cwd())
    grunt.verbose.writelns("cmd", cmd)
    grunt.verbose.writelns("args", args)