attempt to prevent pebble to only read SGV values

Try to avoid reporting null for pebble by only considering SGV
records.

Many thanks to @elute for raising flags on this.
fix mmol panning to show mmol

Fixes a bug where panning would show "HIGH".
when a recent MBG is received via the api and pushover is configured send a notification
a simple script to post an MBG
changed offset to 10 minues; store/check lastMBG time to prevent sending dupes
Merge pull request #200 from nightscout/wip/fix-null-pebble

attempt to prevent pebble to only read SGV values
Merge branch 'dev' into wip/mbg-push
Merge pull request #204 from nightscout/wip/mbg-push

Send Pushover notification when MBG is received via the api
bump version to 0.5.0
Merge pull request #14 from nightscout/dev

Dev