Removed Date.hx and haxe/Timer.hx.

They are obsolete with Haxe 3, and cause errors.
Split js/Three.hx into many files in js/three/.
Updated the externs to match three.js r57.

Also, updated to use Haxe 3's js.html and js.Browser.window
APIs instead of the obsolete js.Dom and js.Lib.window APIs.
Updated the bundled three.js and three.min.js to r57.
Removed classes that are no longer in main three.js.

Some no longer exist in three.js at all, and some now
live only in the examples.
Moved the bundled three.js to vendor directory.

This keeps it separate from the .hx files, to avoid confusion.
Fixed many errors revealed by the compiler.
Updated the way bundled three.js is embedded.

Old way: Embedded by default, disable with '-D noEmbedJS'
New way: Not embedded by default, enable with '-D embed-js'

This matches the way Haxe 3 does it for JQuery and SWFObject.
Merged epic work from @jacius towards r57 for haxe 3