Do not destroy background thread before application end.
Avoids "QThread: Destroyed while thread is still running" and SIGABRT / core dump.
This error occured when the thread was still reading STDIN (no EOF yet) and the window was closed.
# There migth be memory leaks ouside our program in shared libraries.
# We want to ignore them and focus on leaks in our code.
# To use this ignore list, run with:
# LSAN_OPTIONS=suppressions=asan-ignore.txt
# In Netbeans it should be set in the project properties / Run / Environment
# Would ignore all memory leaks:
# leak:.*
# Ignore particular libraries:
leak:/lib/x86_64-linux-gnu/libdbus-1.so
leak:/usr/lib/x86_64-linux-gnu/libfontconfig.so