Use new vector_math.

Signed-off-by: John McCutchan <john@johnmccutchan.com>
Merge branch 'master' of https://github.com/johnmccutchan/spectre

Signed-off-by: John McCutchan <john@johnmccutchan.com>

Conflicts:
	pubspec.yaml
Use new vector_math repo
Adding AssetPackTrace.
Merge pull request #87 from donny-dont/features/asset_pack_update

Adding AssetPackTrace.
Merge branch 'master' of https://github.com/johnmccutchan/spectre
Fix Copyright to something that has legal meaning.
Merge remote-tracking branch 'upstream/master' into features/gltf_shader
Adding gltf shader program support