Created sbbs_t::batch_upload() and JS bbs.batch_upload()
returns true if one or more blind-uploads were received and all files in
the batch upload queue (if any) were received

The Rainbow Ctrl-A codes (x|X) are not valid for message (there's no universal
ANSI equivalent) - so treat as "invalid Ctrl-A codes" for most (message) uses.
e.g. they're stripped when entered into text with the internal message editor.

sbbs_t::chkpass() and JS bbs.good_password() now default to *not* requiring
the password to be substantially different from the user's current password.
This fixes weird issues where a user that just wanted to add more characters
to their current password woudl not be allowed by cause the new password was
"too obvious"
JS bbs.good_password() now accepts an optional second argumnet: forced_unique
which defaults to false.
sbbs_t::chkpass() (JS bbs.good_password()) would always return false if the
provided password was the same as the user's current password, regardless of
the 'unique' parameter value. Now, only reject unchanged password when unique
is true.

sbbs_t::upload() and JS bbs.upload_file() now accept an optional second
argument: 'filename' which when specified, the function won't prmopt for the
user-supplied filename.

New JS property: file_area.max_filename_length

file_area.min_diskspace, settings, and web_vpath_prefix are now read-only.
These properties should not have been writable.