add compatibility flag

[tomjnixon]

Some systems produce files which don't work with the EAR currently, but could be made to work fairly easily.

We could add a a compatibility flag that enables some tweaks to the ADM before rendering. The same code/interface can be used in the renderer command and the ear-utils regenerate tool.

When the flag is used in the renderer, it should warn about non-compatibility and suggest using the regenerate tool.

The interface could be something like --compatibility=timing,dolby_speakerLabels, with a list of fix names to apply separated by commas. We should also add aliases which apply multiple fixes, and an all mode which does everything.

Proposed fixes:

• timing: same as --enable-block-duration-fix
• dolby_speakerLabels: apply a mapping to speakerLabels to turn RC_* to ITU labels
• extra_pack_ref: remove audioStreamFormat to audioPackFormat references to fix audioStreamFormat x has a reference to both an audioPackFormat and an audioChannelFormat error
• dolby: all 3 above fixes

It would be good to collect more information about how this should work:

• What speaker labels can exist, and what ITU labels should they be mapped to? I've used this before:

  RC_L: M+030
  RC_R: M-030
  RC_C: M+000
  
  RC_LFE: LFE1
  
  RC_Lss: M+090
  RC_Rss: M-090
  
  RC_Lrs: M+135
  RC_Rrs: M-135
  
  RC_Lts: U+090
  RC_Rts: U-090
  

• What fixes are required for different software? I don't have great visibility into this -- I seem to remember the pack reference thing not being required previously, but is for nuendo 11 files.