Multiple lines support (Re-Re-pull-request)

I'm really sorry about submitting so many pull-request.

In previous pull-request, I did not noticed it was not easy to merge. so I recreated new pull-request again based on 'feature' branch.

and this pull-request also include basic touch-reporting support. (instead of adding new delegate protocol, I just added getter method to GraphView. user can use use this getter with usual did[Touch|Release]GraphWithClosestIndex method. It is simpler & easier, I think.)

issue #44 , 1st pull-request #102 , 2nd #103