Fix crash from incorrect metadata name typo reported in AltBeacon#652

Update changelog for release 2.13

update changelog

update changelog for release

optimize Identifier#toHexString() and remove unnecessary calls to imp…

…rove performance

Prepare for release

Fix NullPointerException per AltBeacon#583

add changelog

Prepare for 2.12.1 release

Merge pull request AltBeacon#565 from AltBeacon/prepare-for-2.12.1

Prepare for 2.12.1 release