There are 3 ways to get help:
• weave --help
• weave help
• weave <command> --help
At the moment, only the first one prints the usage instantaneously, the
others go much further in the script and take quite some time, which is
not idea of impatient users.
Note that "help" only works because it's not a recognized command and
ends up in the default case of "case $COMMAND" (and indeed, "Unknown
weave command 'help'" is displayed). This is because handle_help_arg()
always returns true and so the second part of:
handle_help_arg "$1" || handle_help_arg "--$1"
is never evaluated.
This commit changes things a bit so all 3 ways to get help are
recognized early, print the usage and exit.
Damien Lespiau