* Support ! modifier (same as '-')
* Create reusable PopupHelpWidget as self-contained popup that can
be positioned around a parent widget and will follow the movement
and sizing of the window
* Eliminated KEEPASSXC_MAIN_WINDOW macro and replaced with
getMainWindow() function
* Add tests to cover search help show/hide
Performing a dev build against the latest version of Qt failed
because of some deprecated members. They have been replaced
according to the Qt documentation.
Further, Q_OS_MACOS is now the only macro available to identify a
machine running macOS, the others are now deprecated.
See https://doc.qt.io/qt-5/qtglobal.html#Q_OS_OSX and
https://doc.qt.io/qt-5/qtglobal.html#Q_OS_MAC.
The database wasn't saved properly and lockfiles were not removed when receiving the signals SIGINT, SIGTERM, SIGQUIT or SIGHUP. This patch implements signal handling and performs a clean shutdown after receiving SIGINT SIGTERM or SIGQUIT and ignores SIGHUP.
Since this uses POSIX syscalls for signal and socket handling, there is no Windows implementation at the moment.
