Merge pull request #1 from playcanvas/feature/edits

Fixed some typos in attribute editor page
New tutorial: Basic Materials
Added Basic Materials tutorial to index page
Various spelling and grammar fixes.
Tidied up the page on finding assets.
[FIX] Smaller camera priorities are rendered first.
New Tutorial "Using the Asset Registry"
Merge branch 'master' into feature/edits

Conflicts:
	content/user-manual/packs/entities/components/camera.md