Use process.hrtime() for Clock in node.js builds

As discussed in #2975.
Update docs/api/core/Clock.html

Correcting typoon line 44: "btween" --> "between"
Add Maya ASCII JSON exporter
Merge branch 'maya-exporter' of https://github.com/etic/three.js into dev
Merge branch 'dev' of https://github.com/Fox32/three.js into dev
Update docs/manual/introduction/Creating-a-scene.html

fixed typo "height of the are we want" -> "height of the area we want"
This makes sure getShaderPrecisionFormat exists on the context
Merge branch 'master' into dev
changed to undefined
Update examples/css3d_periodictable.html

Removed duplicate initialization of object variables. 
The original table-item-object isn't actually used in the
loops.
Converting strings to floats in STLLoader. Fixes #2986.
Merge branch 'master' into dev
FlyControls improvement suggested by @WestLangley in #2992.
Merge branch 'getshaderprecisionformat' of https://github.com/gero3/three.js into dev
CanvasRenderer: Removed redundant material.map check. Fixes #2994.