Bug 4509 - Makes expand/collapse arrows scalable with font size, adds svg versions for higher res, adds logic for gif fallback
Merge pull request #356 from afuna/gmail-on-wrote-bug4196

(Bug 4196) Add more detection for the "On..." line
Merge branch 'release-1.15' into develop

* release-1.15:
  (Bug 5024) Remove embedded HTML from the plaintext comment notif
  (Bug 5026) Recognize ---Original Message--- separator
  (Bug 5026) Another date format
  (Bug 5026) Limit how many lines back we look
  (Bug 5026) Add yyyy/mm/dd format
Merge pull request #349 from deborahgu/4509

Bug 4509 - Bug 4509 - Makes expand/collapse arrows scalable with font size, adds svg versions for higher res, adds logic for gif fallback
(Bug 5025) Enables markdown parsing for replies-by-email

So. Gmail automatically hardwraps sent messages. We can strive to unwrap
it, with the attendant difficulties (what if the wrapping is in the
middle of an HTML tag? what about multiple line breaks vs single line
breaks?), or we can rely on a library which is meant to handle text like
this.

So. Markdown -- HTML still works, along with the various formatting
shortcuts markdown offers.

For a certain subset of users who regularly use their mobile phones,
this should also be easier than switching keyboards to type angled
brackets/quotes

We use regular markdown, with a variant of @username to refer to a
specific user.