1.5.7 release

* fix for linear seek in audio/webm
* updated build chain to emscripten 1.37.34
* performance optimization for VP8 and VP9 on IE 11
    * roughly 15-25% performance improvement
    * uses direct multiplication instead of slow polyfill of Math.imul
* performance optimization for VP8 loop filter
    * roughly 10% performance improvement in Safari, Edge wasm builds
    * smaller improvement in JS
* performance optimization for Opus audio
    * now compiled with optimization, about 4x faster
* built module wrappers with closure compiler
    * shaves a few kilobites off load size
* updated audio-feeder to 0.4.9
    * volume changes now apply immediately on IE
    * float precision for audio on IE

1.5.6 release tag

* detect and work around WebAssembly failure on iOS 11.2.2/11.2.5

1.5.5 release

* allow linear seeking on WebM files without cues, such as audio/webm

1.5.4 updates

* updated yuv-canvas to 1.2.1
    * fixes playback on iOS 9
* fix loading of WebM files under 256kb

1.5.3 release

* fix for canPlayType() for WebM
* updated build chain to emscripten 1.37.28
* minor internals refactoring

Beware that iOS 11.2.2 does not work with the wasm build;
that is a bug with WebKit and will be fixed upstream.

1.5.2: fixes for WebM, blobs

* content-type fixes
* type detection now from content instead of URL

1.5.1 quickfix

Go back to the URL method when we have bad content-type data
(such as in Safari with the mime type override for binary input)

Branch 1.5.0

* cleaned up console logging
* enable WebM by default
* enable WebAssembly by default if available
* allow memory growth on WebAssembly
* build modules with -O3 instead of -O2
* disabled experimental pthreads build for now
* updated yuv-canvas
    * improved image filtering/scaling on Windows
    * work around broken object-fit on Edge 16
* updated stream-file to 0.2.1
    * fixes error on abort during network load

1.4.2 point release - fix 4:2:2 and 4:4:4 subsampling in VP9

Output path worked fine for Theora already, so just needed to
adjust the reported chroma width/height based on the pixel format
in the vpx wrapper.

Note that changing width/height from the values reported in the
container will still blow up.

Tested with bvibber#471 (comment)
and generated files locally.

Fixes bvibber#471

1.4.1: quick fixes for seek after load