Changes to get rid of most of the remaining usages of deprecated guile

[Linas Vepstas]

Log Message:
-----------
Changes to get rid of most of the remaining usages of deprecated
guile gh_* routines.  The file engine-helpers.c also has whitespace
changes where tabs were expanded to 8 spaces (I have set ts=3, so
mixed tab/space indentation looks terrible). I beleive that the
changes are all good, but if you suspect the worst, you can revert by
fishing out the cvs tag 'pre-gh-deprecate'.

Some of the gnome files weren't converted, mostly because the
conversions really should be done in the gnome2 branch not this 
branch.

Modified Files:
--------------
    gnucash/src/engine:
        engine-helpers.c
        glib-helpers.c
        kvp-scm.c
    gnucash/src/gnome-utils:
        argv-list-converters.c
        dialog-options.c
        gnc-menu-extensions.c