DFHack tooltips

[myk002]

Tooltips would help players understand the usage of DFHack interface elements. Previous attempts at "tooltip-like" elements added text as a peer widget below the widget that they were annotating. This proved to be inflexible and it wasn't used outside of the gui/blueprint proof of concept.

Now that we have the overlay system, we have a mechanism for displaying ephemeral widgets outside the bounding box of the annotated widget, so we can have a lot more flexibility in how they are displayed and managed.

Here's an idea for an architecture:

• gui.Widget gets a tooltip property, which can be in the format of the gui.Label text attribute
• Add mouse hover detection to gui.Widget. when the mouse is hovered for a configurable delay, the tooltip is triggered. the value of the tooltip property and the global screen coordinates of the associated Widget are passed to the tooltips overlay.
• the tooltips overlay hides any existing tooltip and then finds a screen position where it can display the given tooltip such that it is adjacent to the widget, near the mouse cursor, and still on-screen
• the tooltips overlay monitors mouse position and hides the tooltip when the mouse moves off the associated widget

we don't have a keyboard-specific method of triggering tooltips, though. I'm not sure how that can be handled.

[myk002]

Could add option to have tooltips displayed on the minimap instead of near the cursor, if that's desired