added < > to line text
added new characters
initialise logic before commands
added arrow and enter keys to keyboard.js
added a dict to Logic that contains a mapping between tags and keys
added extra character points and correctly initialised material visibility in letters
Logic now calls init() function on all commands when they are started
added simple ab test command for user interaction
moved key mapping to commands module variable
began work on SongTest command
fixed bug in songDemo causing first note to be omitted
refined song spec
fixed incorrect demo key icon in singer
keyboard letters are now uppercase
first working SongTest command
added simple GoTo command
cleanups
text buffer is not initialised when singing startes
added extra testing logic
songDemo can now cope with songs that don't start or end with blank lines