Dynamic lists

[djowel]

A dynamic list is like a vtile, but with the elements created dynamically, and optimized for speed and efficient memory use. It should be able to present lists with millions of items. I worked on this a few months ago, but postponed merging to develop due to the work on the artist library. Here's a video of a sample scrolling effortlessly over a list with 100,000 elements:

https://www.dropbox.com/s/k4f3brl95dgljih/dynamic.mp4?dl=0

Note that each row is an element that is created dynamically on demand (and deleted when not needed).

[djowel]

Dynamic lists are also useful for generating items for the thumbwheel #231, instead of creating them statically upfront.

[djowel]

Merged to develop. First take.