common: remove meaningless warning

aq=1 is required for cutree. Therefore, aq=1, aqstrength=0 is a valid case for all configs
that want cutree but do not want aq (eg, tune-psnr).
common: enable CUtree by default. tune=psnr is the default setting
common: this check taken care of in encoder::configure()
common: update print params and defaults.

By default, tune-psnr is turned on, which means CUTree is enabled but AQ strength is zero.
common: adjust tabs
common: tune-ssim turns on aq strength