osx: make sure that dialog windows are menu-less

on linux, when modal dialog is opened application menu shortcuts
are not active and user can type characters even if they are
menu shortcuts.
However on OSX it's not so and if shortcut is a normal character
that user tries to type into input field of dialog window,
keystroke will be intercepted by menu and result in connected action.

To fix issue assign empty menu when creating toplevel windows so that
menu-less dialogs wouldn't have any menu/accelerators by default to
avaoid issue. Windows that have a dedicater menu install it later, so
this isn't issue for them (mainwindow, compose, addressbook)

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
osx: make inputdialog menu-less

inputdialog is a bit specialcased since it uses gtk_dialog_new()
instead of gtkut_window_new() as the rest of dialogs so make it
menu-less explicitly.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
osx: disable menu when quicksearch input field is in focus

disable mainwindow menu when quicksearch gets focus so that
user could type in query and restore menu once quicksearch
looses focus.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
osx: set address book specific menubar as application menu

makes AddressBook menubar appear as application menu when
AdressBook window is open.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
osx: add 'make bundle' target to build OS X application bundle

creates application bundle claws-mail.app at $HOME/Desktop/

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
osx: add jhbuild moduleset file with dependencies to simplify claws-mail build

with this claws-mail could be build within preinstalled
gtk-osx env using following command:

  jhbuild build claws-mail_jhbuild.modules

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
osx: make sure that enchant modules are in bundle and could be found

patch relies on libenchant recognizing ENCHANT_MODULE_PATH env variable
to find moles location

Signed-off-by: Igor Mammedov <imammedo@redhat.com>