Replaced Qt 5.15 deprecated method calls

[warricksothr]

trafficstars

Qt Documentation for the obsolete methods

https://doc.qt.io/qt-5/qstring-obsolete.html#split-1 https://doc.qt.io/qt-5/qprocess-obsolete.html#start-1

[ghost]

Even though it says "Some checks were not successful" on the Github thing under your post, it compiled nicely for me with QT 5.15.0

[joshkerr]

Compiled nicely for me to.

[EriksRemess]

Compiled without any issues.