Matrices in an SWF file store their scale/skew components in
in 16.16 format (fbits).
Split `ruffle_core::Matrix` and `swf::Matrix`. `swf::Matrix` now
stores its data as `Fixed16` instead of immediately converting to
`f32`.
If the shape converter encountered a fill/line style with an
ID > the number of styles, Ruffle would panic as it tried to grab
the non-existent style. This could occur if we mis-parsed some
shape data, or the SWF contained incorrect data. Now we the invalid
style is gracefully ignored.
Switch from pixels to twips for internal calculations. swf crate
was updated to add a Twips wrapper-type. Ruffle will use this type
internally for transforms and shapes. This fixes some precision
errors in rendering (see heroes_of_cybertron.swf) and will match
what the Flash Player does internally more closely. (e.g.
DisplayObject x and y will be quantized to 1/20 pixel units). It
is up to the renderer to convert units from twip space to pixels
when rendering.