This also resulted in a refactoring of the Providers and parsing
Exceptions. NumberFormatException and ParseException can now be thrown
directly, the wrapping in a SmackParsingException is down at a higher
layer, i.e. in AbstractProvider.
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.
A start for the new Jingle API. Since Jingle is a single IQ with many
plugable extensions, there are some particularities we need to deal
with, e.g. jingle users have to register with JingleManager.
This is untested code. There may be drangons.