* fix unit test after thread-sorting change (fixes #413)
* don't mark the mail-header-separator as read-only

  this seems to cause problems in some cases, where message-mode
  apparently requires the text to be writable.
* make mu4e-view-url-regexp a public variable

  thus, users can more easily experiment with this
* mu4e: add fallback for `delete-all-overlays'
* mu4e/org-mu4e.el (org-mu4e-store-link): Add capture template keywords

For other email links (e.g., wl, mh, gnus), a number of keywords are
defined in org capture templates.  This makes these keywords available
for use in captures from mu4e.

http://orgmode.org/manual/Template-expansion.html

Inspiration from Roelof Burger
https://groups.google.com/d/msg/mu-discuss/4sffZofVKAY/aVTdVYoVyiUJ