Added panning support for touch based input.
Added panning support for touch based input.

Benvii/pannellum,Benvii/pannellum,mpetroff/pannellum,riuson/pannellum,quentinyang/pannellum,ywjrg/pannellum,mpetroff/pannellum,eric-seekas/pannellum,eric-seekas/pannellum,mpetroff/pannellum,eric-seekas/pannellum,quentinyang/pannellum,psteph801/psteph801.github.io,ywjrg/pannellum,quentinyang/pannellum,ywjrg/pannellum,riuson/pannellum,Benvii/pannellum,psteph801/psteph801.github.io,psteph801/psteph801.github.io,quentinyang/pannellum,psteph801/psteph801.github.io,riuson/pannellum,Benvii/pannellum,mpetroff/pannellum,eric-seekas/pannellum,ywjrg/pannellum,riuson/pannellum