* Moved common code for drawing about box, info viewer, and other text box menus to a base class; removed the last of the info viewer logic and the multi-line item hack from the base menu class.
* Added previous/next group navigation for general inputs and plugin input selection menus.
* Moved message catalog logic to lib/util, allowing osd and emu to use localised messages.
* Made the base menu class use the UI manager’s feature for holding session state rather than a static map and mutex.
* Improved menu event handling model, and fixed many issues, particularly with menus behaving badly when hidden/shown.
* Added better support for menus that don’t participate in the usual menu stack, like the menuless sliders and the save/load state menus.
* Made a number of menus refresh state when being shown after being hidden (fixes MT08121 among other issues).
* Fixed indication of mounted slot option in the slot option details menu.
* Improved appearance of background menus when emulation isn't running - draw all menus in the stack, and darken the background menus to make the edges of the active menu clearer.
* Fixed locale issues in -listxml.
-debugger: Made GUI debuggers more uniform.
* Added new memory view features to Win32 debugger.
* Fixed spelling of hexadecimal in Cocoa debugger and added decimal address option.
* Fixed duplicate keyboard shortcut in Cocoa debugger (Shift-Cmd-D was both new device window and 64-bit float format).
* Made keyboard shortcuts slightly more consistent across debuggers.
-plugins: Moved input selection menu and sequence polling code to a common library. Fixed the issue that prevented keyboard inputs being mapped with -steadykey on.
-docs: Started adding some documentation for MAME's internal UI, and updated the list of example front-ends.
-Regenerated message catalog sources. For translators, the new strings are mostly:
* The names of the inputs provided by the OS-dependent layer for things like fullscreen and video features. These show up in the user interface inputs menu.
* The names for automatically generated views. These show up in the video options menu - test with a system with a lot of screens to see more variants.
* The input macro plugin UI.
* A few format strings for analog input assignments.
* A few strings for the about box header.
