Picroft alsa fix; Verbose skills logging; Listening sound; NATO Phonetic Pairing code

This release includes several enhancements as well as a bug fix for Picroft alsa playback issues.

For Picroft:

• A configuration setting was added for playing wav files. We found that specifying a hardware device for aplay will fix a Raspberry Pi specific ALSA/PulseAudio issue. This can also be used to interact with other audio systems. The new setting are "play_wav_cmdline" and "play_mp3_cmdline", which can be overridden in your /etc/mycroft/mycroft.conf file.
  PR #514 #514

For Everyone:

• We added more verbose skill service logging, such as where skills are loaded from and what intents are registered.
  PR #513
• A wake word detected sound has been added for better interaction. This wav file is configurable as well for your own custom sound!
  PR #506 #506
• When pairing your device it could be difficult to understand the spoken code. To help with this, we added a NATO-inspired phonetic spelling, such as "C as in Charlie"
  PR #502 #502
• Load data files for skills automatically when loading the skill. Skills no longer need to call self.load_data_files(dirname(file))
  PR #499 #499
• The Adapt intent parser version used has been upgraded to 0.3.0
  PR #496 #497