Frame counters and ping packet

Overview

This release includes two major new features:

1. Frame counters in downlink packets

This enables reliable GSE frame logging in the face of packet loss, which was an issue in the FOXSI-4 flight. Both Formatter and GSE frame counter behaviors are backwards compatible, so this release can be still used with GSE v3.1.0 and earlier.

2. Ping packet transmissoin

This is a new 46 byte downlink packet that the Formatter sends on startup. The packet contains software status information, but the presence of the packet alone can be used to indicate Experiment aliveness in the GSE.

Changes

• Documentation updates by @thanasipantazides in #77
• Added some thoughts on the main README. by @KriSun95 in #78
• Documentation for systemd, systemctl, and formatter.service by @thanasipantazides in #80
• Add downlink frame counter and global health packet transmission by @thanasipantazides in #75

Full changelog

v1.2.2...v1.3.0