Started on integrating indexed db

Are thinking back and forth about using sync. vs. async API for
indexeddb since i am using a webworker for importing fit file. Some
info. indicates that sync. api can not be trusted/are
implemented->prefer async. for now. it seems to work
Able to store a simple object
Things are working at the moment....
Moved functions from .prototype.* as inner function

I had trouble with "this" reference from callbacks on .prototype.*
functions
Able to write records to indexedDB

Had trouble because I forgot the right keypath = timestamp.value (i used
only timestamp in the beginning)
Fixed better error reporting

console.* messages now self.postMessage in webworker
Writes UTC timestamp to indexed DB

Better to deal with UTC time than Garmin time
Persist lap,session and hrv data to indexed DB
Added event properties