ZephCore 1.18.1-zephcore

Half-hour and 45-minute timezones on the on-screen clock, the clock zone on repeater screens, and a
Zephyr update.

Half-hour timezones on the clock

set tz.offset now takes half and quarter hours, as upstream MeshCore now does (after its 1.18.0):
set tz.offset 5.5 for India (+5:30), 5.75 for Nepal (+5:45), -3.5 for Newfoundland. The
display shows the zone as UTC+5:30. Values that are not a whole quarter hour are refused, and
get tz.offset now always prints at least one decimal (2.0, 5.75). As before, only the
on-screen clock moves; the node's own clock and every timestamp it sends stay UTC.

Repeaters and room servers with a screen now show their clock in the zone you set. Before, they
accepted set tz.offset but kept showing UTC.

If you go back to an older ZephCore, a half-hour setting reads as the whole hour below it (5.5
becomes 5).

Other changes

• WiFi companions no longer freeze when the app stops reading. If an app connected over WiFi
  stopped reading (for example in the middle of a contact sync), the node could stop answering on
  USB, Bluetooth and WiFi, and stay stuck as long as that connection stayed open. The node now
  drops such a connection after 2 seconds, and the app can reconnect.
• set leds.hb off and hb now also stop the message blink. Before, a node with the heartbeat
  LED off still flashed on every DM and channel message. set leds on with set leds.hb off now keeps
  a T1000-E dark in use while it still blinks three times when you switch it off with the buzzer muted;
  set leds off keeps it dark at power-off too.
• Zephyr updated to b70dbaf045e. A GPS receiver that fails to start on the first try is now
  really tried again (the two retries did nothing before), and on boards with external flash a
  failed start of that flash is retried at the next mount instead of staying failed until reboot.