Fix issue where first frame emitted would be invalid.

Note that this call to `runAnimationLoop` was [originally added](https://github.com/leapmotion/leapjs/commit/1f40ff3a198db8b70f9333c87f82c6bed2ae8a12) to allow
looping without there being frames.  However, that functionality seems
broken regardless, and perhaps should be deprecated, as there’s nothing
wrong with people running their own loops for leap-independent
animations.

See: https://community.leapmotion.com/t/cant-set-interbox-center-since-i-changed-from-lib-v0-4-1-to-v0-6-0/1194/3