Fix enrolment in line with PZH user identity changes

A number of changes at the PZH and PZH web server mean that
the PZP was not enrolling properly.  This has now been fixed.

In addition, the PZP will now report when enrolment was a
success or not (at least in some cases) and the new PZH and PZHWS
code should be a bit friendlier.

Jira issue: WP-959
Remove unnecessary message validation in pzp_receiveMessage.js

Jira issue: WP-959
Add arbitrary origin to handleProcessedMessage.

Jira issue: WP-959
Initial fix for tests (not complete)

Jira issue: WP-959
Test fixes for this branch

Jira issue: WP-959
Merge pull request #22 from jplyle/fix-enrolment-new-pzh-v2

Fix enrolment in line with PZH user identity changes