Declare the one routine exported by "gtk/filter_prefs.c" in
"gtk/filter_prefs.h" rather than in "gtk/main.h". Declare
"E_FILT_TE_PTR_KEY" there, as well, rather than in "prefs_dlg.h", as the
filter-editing dialog box is no longer a preference tab.
Don't include "prefs_dlg.h" unless the stuff declared therein is of
interest.
Fix "gtk/find_dlg.c" to fire up the filter-editing dialog box, not the
no-longer-extant preferences tab for filters, if the "Filter:" button is
clicked.
svn path=/trunk/; revision=1619
