Merge pull request #24 from agricocb/master

 Added the Hybrid map type and cleaned up some constraints, added Grace's icons
Merge pull request #25 from agricocb/master

Season selection in Settings and Filter page preparation
Phone call not quite working

Got the navigation to About view corrected again.

Put code in to make a phone call (my home number is in there for
testing) but when I run it on my phone, it’s not working yet.
Fix for non-responding telprompt:// link.  Hasn't been checked yet, since the iOS simulator won't do telephone calls (no phone app), and I can't try it on a real iPhone until I go to work.
A few more fix-ups to prepare to merge Grace's one-touch-call feature
Merge branch 'grace/phone-calling'