ui: Improve option processing and help output.
* haunt/ui.scm (%common-options, %default-common-options): New
variables.
(simple-args-fols, show-common-options-help, leave, string->number*,
load-config): New procedures.
(haunt-error): Remove.
(show-version-and-exit): Actually exit. Add 'name' argument.
(haunt-main): Use new 'show-version-and-exit'.
* haunt/ui/serve.scm (show-server-help): Remove.
(show-help): New procedure.
(%options, %default-options): New variables.
(haunt-serve): Use SRFI-37 option processing.
3320a67edb