Docker fixes

[leftshift]

The docker files and docker-compose.yml had various little problems:

• The config in docker/tanner/dist/config.py wasn't up-to-date, so tanner didn't actually start.
  Overriding the python config file is probably not the best way to do this anyways, but this fixes it for now
• phpox didn't work due to a missing package and different binary names
• various directories needed to be writable

Also, I backported phpox/#5. Again, this is required because sandbox.py is overwritten to change config values, which probably isn't the nicest way to do this

[coveralls]

Pull Request Test Coverage Report for Build 775

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 55.705%

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Totals
Change from base Build 756:	0.0%
Covered Lines:	913
Relevant Lines:	1639

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💛 - Coveralls

[afeena]

Thanks for the contribution! (and sorry for long waiting)