Note that the WebGL build uses filameshio, but Android does not. Our
Android samples therefore do not yet understand the compressed format.
For web, I measured the before / after:
```
BEFORE: filament.wasm = 505796, suzanne.filamesh = 521476
AFTER: filament.wasm = 510915, suzanne.filamesh = 333489
```
Issue #558
This adds a few new functions to the JavaScript bindings. It also adds
our JavaScript docs into the CMake build system for machines that meet
the Python requirements.
While this solves the builder leak, it does not solve the tiny leak
incurred every time you call `getInstance` on a component manager
without calling embind's `delete` method afterwards. Since there's no
way to auto-delete component instances, this CL fixes up our sample
code and docstrings.
Fixes#429
