bootstrap: add support to local files
bootstrap: fix documentation to reflect new capability
bootstrap: rename url to src for consistency with documentation
bootstrap: add support to stdin
bootstrap: document stdin
Call help() before loadconfig()

This avoids annoying error messages from config files being debugged
when running 'mr help'.
Fix vcsh_trusted_checkout
Merge branch 'early_help'
Merge branch 'local_bootstrap'
Merge branch 'fix_vcsh_trusted_checkout'