Fix doc on 'make cold'

Closes #1873
Trim package messages

makes it easier to layout in opam files
Consistent cleanup of temp files for parallel and seq processes
Allow pin --kind http, since it's now supported
Warnings and spelling
Fixed compat printer for 1.1

there still weren't enough parens
Merge pull request #1890 from OCamlPro/various-fixes

Fixes compat mode, some doc and spelling, allows pin --kind http