build: warnings now displayed inline on terminal
build: warnings now displayed inline on terminal

Non-fatal warnings are now displayed inline on the terminal, and will
not be piped through to the pager unless there was a non-zero exit code
somewhere. This should avoid some of the confusion from users when faced
with a terminal full of warnings...

MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3