CRM-14516 - enable CiviCRM shortcode button for all post types, default or custom
better detect ajax and other non-page requests to ensure that content-wrappers etc are not included for ajax and snippets;
problem introudced by https://github.com/civicrm/civicrm-wordpress/commit/b9011c2adad0bd245836d1705f580553df78540b
rename to avoid double-negative poor readability;
fix bad function call;
expand to include ical;
check for '/civicrm/' in request;
add usage of isPageRequest for registering wp init callback;
put CiviCRM on the top of the left-nav menu, this makes accessing CiviCRM on a WordPress site much more convenient
CRM-14971 - civicrm/contact/imagefile does not participate in WP's loop
CRM-14989 don't set alreadyInvoked as true till yr actually invoking
introduced in 45d8c9c when the preceding conditions were moved

----------------------------------------
* CRM-14989: WordPress plugins that process the_content cause prevent CiviCRM invoke
  https://issues.civicrm.org/jira/browse/CRM-14989