Add some slop to help stick chat to the bottom.

Plus, add some debugging to help identify chat scroll problems
that codexians are having.

Change-Id: If223419cc8dae6670cdb3344c53ce6e8c88bc7d1
Add checkbox to allow hiding unsolved puzzles.

This is kinda a hack, sorting by status will be a better long-term
solution.  But this will do for this year's hunt.

Change-Id: Ib057f6da330b625040f411d4399b663fb053bd7f