(Hopefully) this makes implementing updaters using external libraries easier on other platforms. To implement an updater on a new platform, create a new class that implements the pure virtual methods from `ExternalUpdater` and add code in the `UpdateChecker` initializer to initialize the new class.
- The launch option is no longer empty.
- The program now checks on startup whether an instance is selected to decide whether to disable instance options.
Also, get rid of a dynamic cast.
It wouldn't bring much utility.
- The keyboard shortcuts for copy/paste/etc. already work and are well-known. The menu bar likely doesn't need to advertise them.
- There's not very many places you would be able to use these options in the main window (because there's not many places to type stuff in the main window). It would only be applicable on systems with a native menu bar that shows in all other windows as well (but again, the keyboard shortcuts still work).
Also, rename `actionWiki` -> `actionOpenWiki` to match the corresponding `on_actionOpenWiki_triggered`
The code is now much cleaner.
Because the actions already present are enabled elsewhere even when the menu bar is hidden, keyboard shortcuts added to them automatically work regardless of whether the menu bar is visible. This means that the hacky workaround related to this can be removed.
Systems with native menu bars show the same menu bar for all child windows. As a result, you cannot assume that the menu bar's parent (the `MainWindow`) will be the window in focus.
Only applicable for systems without a native menu bar (i.e. almost anything that is not macOS or Ubuntu Unity). On these systems, the menu bar appears on top of the window, which does not look good next to the tool bar already up there.
When the menu bar is hidden, the keyboard shortcuts set by the menu bar are disabled. They should always work, so this also adds a workaround for that.
Some stuff still needs to be fixed:
- The close window option always closes the main window, even if it is not the currently active window (only applicable on systems with native menu bar)
- None of the (text) editing actions are enabled
- Actions related to instances should only be active when an instance is selected
- The open wiki option ("PolyMC Help") needs to be implemented
- Delete instance keyboard shortcut does not seem to work on my system. Test further
- It would be nice if the profiles menu had all of the logged in accounts, and if they could be selected from that menu (preferably with keyboard shortcuts, probably Ctrl + 1, Ctrl + 2, ...)
