Remove all remaining GParamSpec name and blurb strings (and fix
indentation while we're there), and add G_PARAM_STATIC_STRINGS to all
paramspecs that were lacking it.
NmtNewtForm is an NmtNewtWidget, but previously it was only realizing
its child, not itself, which is technically wrong (though it had no
noticeable effect until get_realized() was added).
Make all the signals RUN_FIRST instead of RUN_LAST. In particular,
this fixes a crash when creating a new connection and activating the
listbox directly, in which case nmt_newt_listbox_activated() was
running after NmtAddConnection:create_connection() had already quit
the form and unrealized the listbox.
