Basic but robust PID library

Dependents:   ESP8266_pid_mtrPos_webserver_SDcard_v2 ESP8266_pid_mtrSpeed_Webserver_SDcard ESP8266_pid_spd_and_pos_webserver_SDcard ESP8266_pid_redbot_webserver ... more

PID.cpp/shortlog/shortlog@0cf2f6d13c71: not found in manifest