OP-1524 Added CharFieldTreeItem and the check for the 'char' unit in array fields.
OP-1524 Added Array tree node value preview.
OP-1510 don't hard code tx_power to 100mW
OP-1522 Robustness of OPLink radio

Increase number of channels to 32 for all bit rates.
Synchronize clock on all channels.
Go into failsafe after 4 or 8 (one_way_link) missed packets.
Don't stay on channel 0 if we dropped a packet.
OP-1526 Apply reverse all motors, tricopter fixes and HexacopterH cleannup
OP-1526 Oups... wrong erase
OP-1526 Do not reverse Yaw tricopter servo with Reverse All motors, the only change is servo neutral. No changes on mixers, ReverveAllMotors is not stored for tricopter.
OP-1526 Better fix : if ReverseAllMotors is checked, store MixerValueYaw as negative value.
Merge remote-tracking branch 'origin/next' into thread/OP-1524_Chars_In_UAVOBrowser
Merge remote-tracking branch 'origin/laurent/OP-1526_Reverse_all_motors_not_working' into next
OP-1530 Use rfm22b_dev->num_channels

Use the number of allocated channel from the num_channels field
in the pios_rfm22b_dev struct rather than from the maximum number
of possible of channels given the configured speed.
Merge remote-tracking branch 'origin/havyan/oplink-0' into next
OP-1532 fix non-ppm mode

Always send packets from the coordinator.
Previously the coordinator only always sent packets
on channel 0. This scheme doesn't work with
with the change to use 32 channel.