Merge branch 'master' into version

Simplify benchmarks & enable them on all devices. (tensorflow#383)

This PR:
* Enables benchmarks on all devices (whitelisted in support.js)
* Makes buttons mobile friendly with MDL.
* Adds viewport meta to the page so it scales for phones
* Moves common benchmark logic to `benchmark_util.warmupAndBenchmarkGPU`. This function warms up the GPU, times, and returns the result, and it changes functionality based on whether timers are enabled.

update version

Update to version 0.3.9. (tensorflow#351)

Add gl.readPixels check to isFloatTextureReadPixelsEnabled for Safari. (

tensorflow#350)

Clone input for reshape nodes on the graph. (tensorflow#341)

fix line length (tensorflow#305)

Fix bug in Environment. Don't check for color ext in webgl1 (it's imp…

…licitly enabled) (tensorflow#301)

0.3.0

Change conv2d to match TF API (tensorflow#67)

* update the readme and npm package

* update readme

* change conv2d api to take padding same|valid

* Merge branch 'master' into conv

* move logic to math

* some progress

* Merge remote-tracking branch 'origin/master' into conv

* Migrate all conv-related ops

* rename conv2dTranspose to conv2dDerInput

* switch shader indexing from float to int

* revert graph_runner_test

* self review

* Merge remote-tracking branch 'origin/master' into conv

* merge with the branch int_indexing

* fix typos in shaders

* merge with master

* update pool ops

* remove commented out code

* simplify api

* added unit tests for conv/pool

* add doc

* Merge master into conv