Fix AudioClip I/O

[MaigoAkisame]

The existing code does not read and write audio signals without changing them.
I've fixed some of the related code, and added a test_audioclip_io test to ensure the audio does not change during I/O.

• I have provided code that clearly demonstrates the bug and only works correctly when used with this PR
• I have added suitable tests to the test suite in tests/
• I have properly documented new or changed features in the documention or in the docstrings
• I have properly documented unusual changes to the code in the comments around it
• I have made note of any breaking/backwards incompatible changes

[coveralls]

Coverage increased (+0.5%) to 65.24% when pulling 622cbda on MaigoAkisame:master into 710c6df on Zulko:master.

[coveralls]

Coverage increased (+1.9%) to 66.756% when pulling a696e13 on MaigoAkisame:master into 6057cf0 on Zulko:master.

[MaigoAkisame]

All checks have passed!

What's the next step to have this merged?

(It's my first time to make a pull request, so forgive me if I'm asking anything stupid)

[tburrows13]

Hey @MaigoAkisame thanks so much for making this PR! You've done everything you need to for now, it is just waiting for a maintainer to check that we're happy with it and then we can merge it into the master branch.

[MaigoAkisame]

Thank you!

[MaigoAkisame]

There has been no activity for almost 2 weeks. Is someone gonna merge this?

[tburrows13]

Closes #1174. Thanks

[tburrows13]

Sorry, my mistake. Please merge the changes back in at MaigoAkisame#1.

[MaigoAkisame]

Is that something I need to do? What do I need to do exactly?

[tburrows13]

Please just merge MaigoAkisame#1, and I think that I can sort the rest out after that. This is totally my fault, but I can't work out how to fix it without you doing that.

[MaigoAkisame]

Sure! I just did it.

[tburrows13]

Great, I'll merge when the tests finish. You'll be happy to know that this PR fixed #1174 perfectly.