Removed "label" properties which no longer have any function.
Labels are still used as layer names and as identifiers for sending
behaviors between sides of a split keyboard, so those have been left
alone for now.
* Refactor common parts of the Microdox sheild into a separate file. This is in preparation for adding Microdox V2 as another shield in the same directory.
* Refactor Microdox keymap into a common file in preparation for Microdox V2
* Add Microdox V2 shield definition
* Added a README to explain v1/v2 differences.
