Escape HTML entities on the UI layer

Closes #173
Map scroll wheel events to up/down commands (#165)
Fix tests
bump 0.2.20
Typo
handle mouse events other than scrolling
ignore all mouse events in editor mode
Merge pull request #177 from hrzhu/fix-mouse-click

turses crashes on mouse click(other than scrolling)
Add a Bitdeli badge to README
Merge pull request #178 from bitdeli-chef/master

Add a Bitdeli Badge to README
Move badge to the top of README
Filter input that turses currently doesn't handle

Closes #179
Closes #185
bump 0.2.21