Add smack-java7 declarative service

So that everything is correctly initialized. Otherwise we get an NPE
like:

02:55:01 PM SENT (242792115): <auth xmlns='urn:ietf:params:xml:ns:xmpp-sasl' mechanism='DIGEST-MD5'>=</auth>
02:55:01 PM RCV  (242792115): <challenge xmlns="urn:ietf:params:xml:ns:xmpp-sasl">cmVhbG09ImVjLXhtcHAiLG5vbmNlPSJyWWpCYj Znc1I4WUVKZXNZUXV2bXBFQWNoRVVGRGowTnJnUFcxRjFmIixxb3A9ImF1dGgiLGNoYXJzZXQ9dXRmLT gsYWxnb3JpdGhtPW1kNS1zZXNz</challenge>
org.jivesoftware.smack.SmackException$NoResponseException
    at org.jivesoftware.smack.SASLAuthentication.authenticate(SASLAuthentication.java: 247)
    at org.jivesoftware.smack.tcp.XMPPTCPConnection.login(XMPPTCPConnection.java:374)
    ...
    at org.osgi.util.tracker.ServiceTracker$Tracked.customizerAdding(ServiceTracker.ja va:932)
    at org.osgi.util.tracker.ServiceTracker$Tracked.customizerAdding(ServiceTracker.ja va:1)
    at org.osgi.util.tracker.AbstractTracked.trackAdding(AbstractTracked.java:256)
    at org.osgi.util.tracker.AbstractTracked.trackInitial(AbstractTracked.java:183)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:317)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:261)
    at com.foobar.mgmt.tree.xmpp.skeleton.impl.activator.Activator.start(Activator.ja va:33)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextI mpl.java:711)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(Bundl eContextImpl.java:702)
    at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextI mpl.java:683)
    at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java :381)
    at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.j ava:390)
    at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java: 1176)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartL evelManager.java:559)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartL evelManager.java:544)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelMa nager.java:457)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(Star tLevelManager.java:243)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartL evelManager.java:438)
    at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartL evelManager.java:1)
    at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.jav a:230)
    at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.j ava:340)
Sep 18, 2014 2:55:06 PM org.jivesoftware.smack.AbstractXMPPConnection callConnectionClosedOnErrorListener
Warnung: Connection closed with error
java.lang.NullPointerException
    at org.jivesoftware.smack.util.stringencoder.Base64.decode(Base64.java:87)
    at org.jivesoftware.smack.sasl.SASLMechanism.challengeReceived(SASLMechanism.java: 206)
    at org.jivesoftware.smack.SASLAuthentication.challengeReceived(SASLAuthentication. java:325)
    at org.jivesoftware.smack.SASLAuthentication.challengeReceived(SASLAuthentication. java:310)
    at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.parsePackets(XMPPTCPC onnection.java:1105)
    at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.access$200(XMPPTCPCon nection.java:969)
    at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader$1.run(XMPPTCPConnecti on.java:988)

SMACK-343
Make smack-android/smack-java7 declare minimal dependencies
Add support for XEP-0352: Client State Indication

SMACK-607
Filter sun.security.* from smack-java7 Import-Package

Quoting Jens Offenbach:
"The header entry [sun.* in Import-Package] MUST be removed because
its a native package and not exported by the OSGi framework. The bundle
cannot be resolved. It is up to the OSGi framework deployer to declare
this package as beeing "bootdelegated". This tells the classloader of
the bundle to delegate a corresponding package request to the installed
JRE. Only remove this entry and leave the "magic" of resolution to OSGi"

SMACK-343
Add new RSMSet constructors

and fix typo in RSMSetManager
Remove duplicate code in pubusb LeafNode

Make fields of GetItemsRequest and NodeExtension final and use
XmlStringBuilder.
Add ServerPingWithAlarmManager to smack-android
Make smack-android-extensions depend on smack-android

so that Users that want Smack on Android with Smack Extensions just have
to depend on smack-android-extensions.
Add message String to ConnectionException
Add MessageWithBodies and DelayedStanza Filter
Use non-deprecated method in DelayInformationManager
Ensure that Smack is initialized when calling ProviderManager
DisabledSmackClasses now also take package names

So that whole packages can be disabled.
Update flattr link in README.md