Github actions + RStudio Desktop

[meztez]

Added github actions for tests + covr, might need to set repo secret for covr upload

Modified RStudio detection to account for desktop. Safer printing by using Rprintf("%s", str). So imbedded % render correctly on all OS round percent before fixing width as it would not print to set width Finally _isatty on Windows returns int values above 0 when TRUE (not only 1)