Check audio initialization on JS

[soywiz]

#9 (comment)

After updating to Korge 1.11.1.0 the audio stopped working on the JS build.
In the Console it prints the warning:

korau-root-korau.js:8121 The AudioContext was not allowed to start. It must be resumed (or created) after a user gesture on the page.

But I think this already was there before the update.