Raise rcSerialCount to avoid throttle resets

Closes #16

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
HACK: decrease default rate/expo

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
GPS: start parsing on 2D fix instead of waiting on 3D fix

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>