Floating virtual buttons that can trigger key maps

[sds100]

Developer TODO (don't remove)

• update documentation

Requirements
Must have

• Hide the buttons when key maps are paused/resumed.
• Add button to the Key Mapper notification to hide virtual buttons.
• Show a dialog letting them select which app it show the button in. This will add a constraint. Show a little text above the done button letting them know they can change the apps in Constraints.
• Create multiple floating button profiles that have a set of constraints, and a set of buttons.
• Name profiles - use a default based off the constraints.
• Set multiple constraints.

Should have

• Be able to use the same floating button in multiple key maps.

Features

• Listen to constraints so show/hide depending on them.
• Add multiple buttons to the screen.
• User can drag them around anywhere.
• Remember where they were placed when they are shown/hidden.
• Register down and up events from when the user presses down and releases.
• Change the size of the buttons.
• Show an icon depending on the first action. If it is a key event action then show the symbol corresponding to the key code.
• Ability to set a custom icon.
• Change the opacity of the buttons.
• Set custom background color?