Remove user agent sniffing so touch events work on all mobile devices

[eligundry]

I saw that you were manually detecting iPod Touches and iPhones for the touch events, and, as a result, it wasn't working on my iPad or Android devices. So, I went ahead and removed those conditionals so it will work of all devices that support them.

[ARH-Digital]

Glad I found your fix eligundry. It has fixed the issue of not drawing on Android. +1

[gaucho1978]

yes it works on android, but if i zoom the webpage with a pinch, and then i draw, the line is not drawn under my finger, but in another location.

[gaucho1978]

some problems solved: gaucho1978@fe1c437

it is a bug related to offset() call that appears on chrome for android after a pinch.
I solved it.
I also allowed the ability to pinch and pan with 2 fingers and to draw with one finger.
i also made some other minor changes. see them all on the link.