Initial Contribution of ESH WeMo Binding

Signed-off-by: Hans-Jörg Merk <hans-joerg.merk@t-online.de>
refactored initial contribution to make it consistent and more stable and well-behaving

Signed-off-by: Kai Kreuzer <kai@openhab.org>
added new descriptor url method

Signed-off-by: Kai Kreuzer <kai@openhab.org>
Merge branch 'hmerk-wemo_soap'

Signed-off-by: Kai Kreuzer <kai@openhab.org>