Push to version 0.7.9 of denonavr

[ol-iver]

Description:

Push to version 0.7.9 of denonavr includes several fixes

• Fix empty sources list in Zone 2 and 3 at non AVR-X devices
• Add sound mode 'DOLBY HD'
• Add 'Dolby TrueHD' sound mode
• Add sound mode 'DOLBY ATMOS'

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly. Update and include derived files by running python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt by running python3 -m script.gen_requirements_all.
• Untested files have been added to .coveragerc.

If the code does not interact with devices:

• Tests have been added to verify that the new code works.

[andrewsayre]

Can merge when build passes!

[andrewsayre]

Failure is unrelated to PR. Merging.