split off Yutils based bounding box detection from .getMetrics and make it optional
add support for drawings, part 1
add support for drawings, part 1: add table type coercion, accept clip signature in ASSDrawing constructor, create drawing command classes before dumping them in a table (duh)
add drawing section support, part 3: reinsert drawing tags into tag sections on commit; update functions and assertions to accept/acknowledge ASSLineDrawigSections; store valid line section and drawing command classes in the ASSFoundation singleton which is guaranteed to be created last (when all other classes already exist); update ASSLineSection functions to take a table of targeted sections instead of a separate parameter for each type, add a filter parameter in ASSFoundation.instanceOf to accommodate that.
ASSLineContents:new(): make the default drawing state an object so we can access the value property