Merge pull request #346 from bvssvni/master

Added condition compilation for PortAudio
Merge pull request #348 from bvssvni/master

Removed `AudioSDL2` from `GameIterator`
Merge pull request #349 from bvssvni/master

Removed `InteractiveEvent`, added `to_sendable` to `GameEvent`
Merge pull request #350 from bvssvni/master

Making library compile with port audio
Merge pull request #351 from bvssvni/master

Fixed sound stream example partially
Merge pull request #352 from bvssvni/master

Fixed audio_iter example
This fixes #360 and #356 and #355 and #353
Merge pull request #365 from mitchmindtree/master

This fixes #360 and #356 and #355 and #353
Closes #357
Closes #366 and #357
Merge pull request #367 from mitchmindtree/master

examples/soundstream.rs fixes
Made Piston compile without PortAudio settings

Closes https://github.com/PistonDevelopers/piston/issues/371