T-Rex 0.19.7

* ("ethash", "octopus", "kawpow") Improve stability for 30xx series GPUs
* ("ethash") Verify overclock stability after DAG rebuild ("Instability detected" message is printed in case there are issues)
* Add "--gpu-report-interval-s" parameter to control hashrate summary report frequency based on the number of share submissions
* (API) Add new "pause" command for "control" handler to pause and resume mining
* (Watchdog) Display a list of GPUs caused miner restart with "GPU is idle" error

Bug fixes:
* ("x21s") "incorrect size of extranonce2" error
* (UI) Incorrect GPU index in share submission report when "--pci-indexing" mode is enabled
* (API) Miner fails to switch algorithms on the fly for some ""<algo_from>" -> "<algo_to>"" combinations