Add brief documentation of the command-line options accepted by gwave
add menu item to show/raise all of the variable-list windows;
fix VisibleWave-set-tooltip, and call it from new-visiblewave-hook to set
checkpoint work in progress on restoring tooltips
various fixes.
further experimentation with GtkBuilder for dialogs
WIP on gtkbuilder-based way of doing complex dialogs
message typo fixes and Makefile.am improvements contributed by Ahmed El-Mahmoudy