Apply builder pattern to form fields and replace getVariable() with
getFieldName(). Refer to the field name as "field name" instead of
"variable" everyone, just as XEP-0004 does.
Improve the high-level form API: introduce FilledForm and FillableForm
which perform stronger validation and consistency checks.
Also add FormFieldRegistry to enable processing of 'submit' forms
where the form field types are omitted.
Smack also now does omit the form field type declaration on 'submit'
type forms, as it is allowed by XEP-0004.
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>
