Version 2.1.7
This version fixes an incompatibility that has arisen with the release (on January 21, 2016) of Chrome 48.0.2564.82. This update was breaking all Epichrome apps. If your apps no longer start, install Epichrome 2.1.7 and run them again. Each one should offer you the choice of updating to 2.1.7, after which they should work again.
Thanks to ylluminate, evansthompson, msubel, and everyone else who pointed this problem out. Special thanks to breeden for helping test the solution!