Change above-the-fold layout - step 3

* make top of "below-the-fold" be actually above the fold
* put all above-the-fold content except title and more details button
  into that area
* kep below-the-fold area in fullscreen mode when title/credit gets untruncated
* increase title length to 180 (140 before reducing font size) - works nicely on
  my 1600x900 laptop
* remove old styles which were intended to make the button smaller when the
  panel is close but were mostly broken anyway and only caused the button to
  twitch

To avoid redoing all the size calculation logic, we cheat and use a negative
margin to pull the below-the-fold content above the fold.

Change-Id: I18d7bdb7dbbdfb8201c0d66257731febfac31263
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/833
Merge "Change above-the-fold layout - step 3"