Backport pjsip r4896

git-svn-id: http://csipsimple.googlecode.com/svn/trunk/CSipSimple@2428 9f815046-5998-e9c0-b7e2-ac03a23edfa4
Update pjsip to latest trunk (4901)
Disable silk in default build as not available from skype/ms anymore

git-svn-id: http://csipsimple.googlecode.com/svn/trunk/CSipSimple@2429 9f815046-5998-e9c0-b7e2-ac03a23edfa4
Allow tcp in fritzbox as seems required in v6 of firmware
New wizards

git-svn-id: http://csipsimple.googlecode.com/svn/trunk/CSipSimple@2430 9f815046-5998-e9c0-b7e2-ac03a23edfa4