Ticket #9124: Remove horde/Core dependency from horde/Nls.

Ticket #9124: Remove horde/Core dependency from horde/Nls.

Move all of the Horde_Nls:: code dependent on Horde configuration to
horde/Core.  A core dependency has thus manifested itself in a bunch of
framework libraries thought to be horde/Core free (since getCharset() is
dependent on the local Horde configuration).

The following functions have been moved to registry:
Horde_Nls::config -> Horde_Registry::$nlsconfig
Horde_Nls::select() -> Horde_Registry::preferredLang()
Horde_Nls::setLanguage() -> Horde_Registry::setLanguage()
Horde_Nls::setTextdomain() -> Horde_Registry::setTextdomain()
Horde_Nls::setLanguageEnvironment() ->
Horde_Registry::setLanguageEnvironment()
Horde_Nls::isValid() -> Horde_Registry::isValidLang()
Horde_Nls::getCharset() -> Horde_Registry::getCharset()
Horde_Nls::getExternalCharset() -> Horde_Registry::getExternalCharset()
Horde_Nls::getEmailCharset() -> Horde_Registry::getEmailCharset()
Horde_Nls::setCharset() -> Horde_Registry::setCharset()
Horde_Nls::setCharsetEnvironment() ->
Horde_Registry::setCharsetEnvironment()
Horde_Nls::setTimeZone() -> Horde_Registry::setTimeZone()

Horde_Nls::generateFlagImageByHost() ->
Horde_Ui_FlagImage::generateFlagImageByHost()

Horde_Registry::initApp() now accepts the boolean 'timezone' parameter,
which will set the timezone if true.