Amend XDG_DATA_DIRS if not installed in default prefix

This ensures gsettings schemas are properly found

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23225 57a11ea4-9604-0410-9ed3-97b8803252fd
Temporarily use gconf as gsettings backend

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23226 57a11ea4-9604-0410-9ed3-97b8803252fd
Gnc-Prefs: migrate first preference option (first_user) to new preference system

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23227 57a11ea4-9604-0410-9ed3-97b8803252fd
Gnc-Prefs: migrate most preferences found in app-utils

This required  changes in dependent modules as well. And obviously
the gnc-gconf-utils.[ch] files are not removed yet. Too many
other files still require those.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23228 57a11ea4-9604-0410-9ed3-97b8803252fd
Gnc-Prefs: migrate search dialog and saved window geometry preferences

Note: the saved window geometry options (position and size) are
converted into a type that is incompatible with gconf. This has two
consequences:
1. while testing the gconf backend is used by gsettings. The
incompatible option (last_geometry) won't be saved in gconf. You will
see an error because of this. It does work when switching to gsettings'
native backend

2. The old geometry data won't be converted at user migration time (ie
when the user starts gnucash-with-gsettings for the first time. I don't
think this is very dramatical. The next time a dialog is used, the last
saved position is saved again already automatically.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23229 57a11ea4-9604-0410-9ed3-97b8803252fd
GncCurrencyEdit: add gobject property mnemonic

That will allow a one on one mapping between a widget property
and a preference in the preferences backend in a future commit.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23230 57a11ea4-9604-0410-9ed3-97b8803252fd
GncPeriodSelect: add gobject property active

That will allow a one on one mapping between a widget property
and a preference in the preferences backend in a future commit.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23231 57a11ea4-9604-0410-9ed3-97b8803252fd
GncDateEdit: add gobject property "time"

That will allow a one on one mapping between a widget property
and a preference in the preferences backend in a future commit.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23232 57a11ea4-9604-0410-9ed3-97b8803252fd
Prepare preferences dialog to work with gnc-prefs instead of gconf.
The actual migration will be gradually done in future commits.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23233 57a11ea4-9604-0410-9ed3-97b8803252fd
Gnc-Prefs: migrate all GtkFontButton widgets (default_font property)

All GtkFontButtons now use the new preferences backend
so drop the GtkFontButton-Gconf wiring as well.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23234 57a11ea4-9604-0410-9ed3-97b8803252fd
Gnc-Prefs: migrate GtkCheckbutton widgets (and associated preferences) - first batch

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23235 57a11ea4-9604-0410-9ed3-97b8803252fd
Gnc-Prefs: migrate 24hour_clock preference and fix the code
so it actually works. (It's not actively used though in GnuCash)

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23236 57a11ea4-9604-0410-9ed3-97b8803252fd