Introducing Smack's own XmlPullParser interface which tries to stay as
compatible as possible to XPP3. The interface is used to either wrap
StAX's XMLStreamReader if Smack is used on Java SE, and XPP3's
XmlPullParser if Smack is used on on Android.
Fixes SMACK-591.
Also introduce JUnit 5 and non-strict javadoc projects.
instead of throwing XmlPullParserException, IOException and
SmackException.
Add a guard to AbstractXMPPConnection.processPacket() to always re-throw
RuntimeExceptions.
b71039660b made FormField.setType(Type)
throw an illegal argument exception if type is fixed, but the
DataFormProvider was not changed, so it still would call
setType(Type.fixed).
Change DataFormProvider so that the non-argument constructer of
FormField is used when type == fixed.
Data Forms Validation are a part of Data Fields and implemented as
extensions, added to a Datafield.
Data validation extensions are validated before adding to the message,
using the consistency rules as described in the XEP.
Fixes SMACK-621.
Minor modifications done by Florian Schmaus <flo@geekplace.eu>