fix($animate): ensure enable/disable animations work when the document node is used

Closes #4669
docs($provide): fix link to factory section
docs(guide): add link to book
docs(guide): improve links to books

Nested bullet points don't appear very nicely so resorted to nested
heading for the Learning Resources and in particular Books sections.

Closes #4677
docs(guide/directive): fix myDraggable for zoomed page

If you have zoomed into the page in your browser then the screen coordinate system no longer
matches the page coordinate system.  To ensure that dragged elements work correctly when zoomed
we should use pageX/pageY rather than screenX/screenY.

Closes #4687
fix($animate): ensure enable/disable animations work when the document node is used

Closes #4669