CRM-12691 remove references to Create PCP URL from help files since the ...

...page id was not available. Add this info inline to the forms, and generically to the Manage PCP page. Also added the example URL for WordPress, which was missing.

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* CRM-12691: Create PCP link is hard to discover and link in user guide is incomplete
  http://issues.civicrm.org/jira/browse/CRM-12691