Put channel on hold before joining (references #66)

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4398 43c1dc8c-776e-4df2-8ef1-6e829299be21
Conference Updates (fixes #67, fixes #66, fixes #65, fixes #63)

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4399 43c1dc8c-776e-4df2-8ef1-6e829299be21
Fix when building --without-conference

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4400 43c1dc8c-776e-4df2-8ef1-6e829299be21