Smack 4.0.0-rc3-SNAPSHOT
Do not filter groupchat messages without body

for MessageListeners in MultiUserChat

SMACK-568
Fix lost sharedManfiest configuration in build.xml

The configuration of ext.sharedManifest was no longer included (since
39c837190df002fad90be61f22c7ecadc072e263).
Make getMulitipleRecipientServiceAddress() more robust

the method should not throw if one of server's items fail to query.
Improve getMultipleRecipientServiceAddress

and MultipleRecipient (XEP-33) related code in general (e.g. use
constants where possible).

For getMultipleRecipientServiceAddress() this means that
- the "synchronized (services)" block is removed
- ServiceDiscoveryManager is only retrieved once
Add missing mechanism-too-weak SASL Error
Smack 4.0.0
Merge branch '4.0'

Conflicts:
	build.gradle
	smack-extensions/src/main/java/org/jivesoftware/smackx/muc/MultiUserChat.java