jsDoc updates/fixes

[Zetaphor]

This PR updates a number of references to the Vircadia platform in the jsDoc strings, adds two assets to apidocs.overte.org/examples, and fixes a couple typos in existing documentation.

This resolve #523

The changes are as follows:

Fixed URL's pointing to Vircadia CDN

• Audio.playSound
• Script.beginProfileRange
• Script.endProfileRange
• Entities.EntityProperties-Model
• Entities.EntityProperties-ParticleEffect
• Graphics.canUpdateModel
• AnimationCache.prefetch
• A comment in PointerEvent.h

Typo fixes (thanks to @alizardguy for catching these!)

• MyAvatar.getSkeletonOffset was missing a closing parantheses in its example
• MyAvatar.setSkeletonOffset had a colon where there should have been a comma in its example

Added assets

The following assets were copied into /tools/jsdoc/hifi-jsdoc-template/static/examples in order to support the required jsDoc updates listed above

• Silly Dance.fbx was copied from overte-content/marketplaceItems/partyBall/entityResources/resources/animations for AnimationCache.prefetch
• beach-tide-amplified.wav was copied from overte-content/Bazaar/Worlds/Daybreak/content/audio for Audio.playSound