@ashfurrow => Avant Garde font with custom tracking

* Katarina wanted me to replace the avant garde that we've been using with one that has some more space between the letters (which I think is also used on the website). I didn't want to change this in eigen or folio, since it could break a lot of labels, so I made a new branch of artsy-uifonts that includes this new font asset instead of the old avant garde and point to it in eidolon's podfile

* Shortened the titles of long-name switch view buttons so that they look better, with Katerina's approval

* fixed a problem with delete and clear buttons, which I think I probably caused a while ago by accident when making changes. They were wired up not only to the delete and clear IBActions and the corresponding signals, but also to the same IBAction and signal that all the number buttons on the keypad connect to, which was causing the unexpected behavior.
i separated these out because it made it clearer to see what was failing -- before, all snapshots failed but it appears as one failing test, now each snapshot can pass/fail independently