tweak topic view, make last post take full height
Version 0.3.17

-Tweaked topic views, last post button now takes up full height of view
-Tweaked nav drawer background on light themes, should look much better
-Tweaked login dropdown in nav drawer, radio button should not be
present on pre-3.0 devices now
-Tweaked nav drawer item heights to match Android's preferred list item
height
-Fixed nasty bug that caused app to crash if it was opened without a
default account to log in to