Live Search Control

Implements a live search control for user panels/windows, in which the search results are displayed in a modern-looking drop down menu that gets updated with every keystroke. The effect is that the user gets a live menu update as they type. 

A selection can be made with the mouse or by navigating the menu with the keyboard and pressing enter/return. Mouse scroll events are handled as well if the menu is large enough to require it. Users set a trigger function that is activated upon selection of an item.

There's an example implementation that can be run using:   Search#ExampleLiveSearch()

The type of search carried out is determined by the mode:

mode = 0 // Searches a text wave for the search input

mode = 1 // Searches the search folder for any wave that match the search input

mode = 2 // Searches the search folder for 2D/3D waves that match the search input

mode = 3 // Searches for user function that match the search input

My use case has been for selecting a user function from a large-ish library of functions, that is otherwise clunky to navigate through using traditional menus and submenus. 

See the comment header in the .ipf for more clarification on usage and how to set/change the control's parameters after it's already been initialized. 

Works nicely on Igor 8 for mac, *should* be fine for Windows but haven't tested yet.

Edit: This was not added by Ben but by Johan. Strangely I am far from a hacker but accidentally found this bug...