Line rendering now has its own pipeline (removing the texture issue).
Glyph rendering (for fonts) has been reworked to use instanced quad
rendering, with the geometry (position and texture coords) in a static
buffer (uniform texture buffer), and each instance has a glyph index,
color, and 2d base position.
Multiple fonts can be loaded, but aren't used yet: still just the one
(work needs to be done on the queues to support multiple
textures/fonts).
Quads haven't changed much, but buffer creation and destruction has been
cleaned up to use the resource functions.
