merge
Merge branch 'poi_merge'
Merge pull request #1 from luxigo/master

Master
in progress: document main.js
extend new sound with soundList defaults
unset panorama.mode.rotate from panorama.prototype.mousedown hook instead of poi mouseevent handler
set e.target in sound_callback
set panorama.mode.rotate on isLeftButtonDown only
add support for POI as texture with alpha channel
readPixels: inverse vertical coords
minor changes
main.js: wip
main.js: unicorn POI for Alex
Merge branch 'poi' of github.com:luxigo/freepano into poi