Typography updates from typography refresh meeting

* Clean up blockquote display
* Increase line-height for content
* TOC redesign
* hatnote redesign
* Remove thumbnail borders
* Tweak thumbnail captions
* Optimize header font display for Linux:
After doing some research and consulting with Linux Wikipedia users,
it was determined that the way to get the best font rendering in
Linux (i.e. the closest to that desired by the designers) was to
utilize the font fallback mappings in Linux, rather than trying to
specify specific free fonts. This change was the consensus decision
of the refresh meeting, but may be revisited in the future.
* Set article title to 1.8em

Note that infobox changes are not part of this changeset, but will
be in a follow-up change.

Change-Id: I8259c92c6b71ea4be04250ad53b248e2efe7870e
Follow up to Iee3765e940cfd9784c55b6a87a678e41550032a7

For image assets to work correctly we need to keep in sync with
desktop.

Change-Id: Iae1ae9d04eff8264246f1227928d2f60cf56f746
Merge "Follow up to Iee3765e940cfd9784c55b6a87a678e41550032a7"
Merge "Typography updates from typography refresh meeting"