api: add an option to disable the informational SEI message

For regression testing, or comparing outputs between compilers or platforms,
this header is quite unhelpful, so make it optional.
slice: remove set/get methods from ProfileTierLevel, and dead encoder vars
slice: Remove get/set methods from TComPTL
entropy: remove profilePresentFlag argument from codePTL, always 1
entropy: simplify PTL coding, there is only one layer
encoder: keep ProfileTierLevel singleton in the top-level encoder

Remove the copies in the SPS and VPS and remove the TComPTL object entirely,
there is only one level.
entropy: hoist a couple of trivial functions, brace nits

--HG--
extra : amend_source : 493bcfb976aafc469f29e7a68e4b818f0ceef685
TEncCU: remove useless field

There's a global variable for this.
compress: fix for sa8dcost storage in rdlevel 1, 0