(forms--set-minor-mode): Rewrite so that describe-mode

(forms--set-minor-mode): Rewrite so that describe-mode
can parse the value of minor-mode-alist correctly.  The string
" View" is now dependent on the value of forms-read-only.

Documentation: `forms-forms-scroll' and `forms-forms-jump'
now default to nil.
`forms-new-record-filter' and `forms-modified-record-filter'
cannot be redefined as functions.
Commands and keymaps are changed.
Add function key defs.

(forms-version): Docstring includes full RCS id.
(forms-forms-scroll): Defaults to nil.
(forms-forms-jump): Defaults to nil.
(forms-mode-edit-map, forms-mode-ro-map): Additional keymaps
for edit mode and read-only mode.
(forms--new-record-filter, forms--modified-record-filter): Deleted.
(forms-mode): Docstring now includes the key bindings, since
both edit mode and read-only mode must be supported.
Changed `forms-new-record-filter' and `forms-modified-record-filter'
semantics: the variable must point to a function and may
not be defined as a function anymore.
Use three keymaps: `forms-mode-map' (C-c commands),
`forms-mode-edit-map' (normal mode) and `forms-mode-ro-map'
(read-only mode). The maps are not buffer local.
Corrected error message text.
Moved setting up write-file-hooks and revert-buffer-function
to function `forms--change-commands'.
(forms--process-format-list): Changed error messages to be more descriptive.
(forms--set-keymaps): Setup the three keymaps.
(forms--mode-commands): Use new command key bindings.
(forms--mode-commands1): New helper function for `forms--mode-commands'.
(forms--change-commands): Handle setup of
local-write-file-hooks and revert-buffer-function.
(forms--help): Show new command bindings.
(forms--show-record): Replaced `forms--modified-record-filter' by
`forms-modified-record-filter'.
(forms-jump-record): Changed error message.
(forms-toggle-read-only): New function.
(forms-view-mode, forms-edit-mode): Deleted.
(forms-insert-record): Replaced `forms--new-record-filter' by
`forms-new-record-filter'.
(forms-insert-record, forms-delete-record): Disallow in read-only mode.
(forms-prev-field): New function.