It shouldn't be RGUI browser dir. Instead it is a more developer centric
option for when libretro apps are distributed (along with RetroArch for
example). Also facilitates a standardized assets folder later on if
applicable.
Allow requesting to browse for a directory.
Allow requesting the browser to display an option to return a black item.
Swap the ‘Up’ and back buttons in the browser.
Properly reset string settings that were changed in rgui.
The file browser will start in the directory of the currently seleected file.
The setting menu will display only the filename instead of the full path.
Path settings can specify a list of extensions to search for.
