Blind attempt to fix Chrome>55 touchscreen behaviour

[IvanSanchez]

This is a blind (read: completely untested) attempt to fix #29. Listening to PointerEvents when L.Browser.pointer is true should alleviate all the problems. Hopefully this will not break other touchscreens.

[w8r]

@IvanSanchez thanks a lot! Currently I have no device to check it, I will merge it as soon as I will try it out

[peppierre]

@IvanSanchez fyi seems that this commit breaks drag functionality in case of mouse devices. would you pls double-check whether this symptom is real or not?

[Damorck]

Were the any tests telling if it worked or not?

[w8r]

does anyone have a device to check it?

[Damorck]

I´ve tested with Chrome 59 on Huawei P9 Lite and hasn´t fixed the issue.