Added support for Elso protocol


git-svn-id: svn://svn.code.sf.net/p/fhem/code@5057 2b470e98-0d58-463d-a4d8-8e2adae1ed80
added: error handling for missing LWP::ua to avoid fhem crash

git-svn-id: svn://svn.code.sf.net/p/fhem/code@5058 2b470e98-0d58-463d-a4d8-8e2adae1ed80