Use PEP (and XEP-0222) for XEP-0292

[singpolyma]

While the existing version says this was rejected by community consensus, since then the consensus of most implementations is to use PEP directly even though it was never specified to work, and that the raw-IQ protocol adds complexity. This update removes the raw-IQ mode and specifies the reuse of PEP.

[CLAassistant]

All committers have signed the CLA.

[Kev]

@stpeter You're probably the easier of the two Authors to get hold of to approve this :)

[Kev]

This also needs a version block.

[stpeter]

+1 LGTM