FIXED: changeZoomLevel signature
FIXED: using an angular binding (id={{myId}}) for panzoomId didn't work
ADDED: karma test to cover this case
ADDED: config.inverMouseWheel option that will invert mousewheel direction
if set to true (defaults to false)
UPDATED: bin files (guess there's no gulp task for that ?)
Merge pull request #27 from warpdesign/master

Interpolated id fix and more