Several minor changes:
* Moved the Picroft version scheme to be date-based
* Boot now displays both mycroft-core and Picroft build version numbers
* Hide excessive wget messages, only show errors
* Return to home directory at the end of the script
* Tweaked some messages

* Cleaned up mycroft.conf
  - removed unused 'update' and 'test' values
  - removed setting which forced Picroft to use mimic
  - removed setting which forced mimic to use Alan Pope voice