Fixed unconnected traces

more decoupling caps and remove one GND from P22

Merge pull request #400 from dominicgs/firmware_compatibility_check

Optional spi flash status read

Add flash status read

Merge pull request #403 from muellermartin/fix-host-README

Fix a few typos in README for host tools

Fix some Markdown syntax issues

Merge pull request #402 from mokipcs/master

Fixed bug in rx_callback(), where time_stamp.tv_usec was sent through modulo before time_stamp.tv_sec was updated.