--max command

[Cyan4973]

New --max command, which attempts to provide the best possible compression ratio, at the expense of everything else, cpu and memory, by pushing all parameters to their maximum value.

Warning: this setting is extremely wasteful, and not meant to be practical for larger files,
as illustrated by the following example:

compressing enwik9 (1,000,000,000 bytes) at --max level, on a i7-9700k platform:

level	cSize	cTime	cMem
--ultra -22	213,898,083	~6 mn	~ 3 GB
--max	202,507,076	~72 mn	~ 18 GB