implemented EventTarget (including test)
Wall: added events connected and disconnected

added utility function error_json
moved call from ClientUi to Ui
set display style to fullscreen
updated test command in README
ported (basic version of) m2pong to Wall

implemented motion instead of touch control
Merge pull request #49 from NoyaInRain/pyng

Ported (basic version of) m2pong to Wall