Handle no normals

[BeebBenjamin]

Fixes #19 by checking if albedo or normal maps are available, and it not rendering null in place of the Torch component and it's new parent container.

Fixes #5 by making the Torch button float above the OSD container like with mirador-image-tools.

• Restyled the Torch component and added a parent container that could be added to later with additional tools.
• Restricted the removal of handlers to those linked to viewport-change only.
• Downgraded to react 16 because Mirador only supports v16.
• Reformatted curly parentheses white spacing style to be consistent with other react projects.

[BeebBenjamin]

Needs no normals handling adding, hence the name of the branch