back to # and b for translatable strings in CPP files

due to a bug in lupdate, see
https://bugreports.qt-project.org/browse/QTBUG-35164
revert back to plain # and b in CPP files

but also make these strings translatable
Merge pull request #697 from Jojo-Schmitz/24574-flat-and-sharp-symbols-in-tooltips-and-dialogs

back to # and b for translatable strings in CPP files