updated bind function for Windows support
updated bind function for Windows support

changed bind function to register 'touchstart' listener only if !navigator.pointerEnabled && !navigator.msPointerEnabled. this works on windows 10 desktop and phones (navigator.pointerEnabled = true) and also on iOS and Android.

``` js
console.log('iOS', window.navigator.pointerEnabled, window.navigator.msPointerEnabled) // iOS undefined undefined
console.log('Android', window.navigator.pointerEnabled, window.navigator.msPointerEnabled) // Android undefined undefined
console.log('Windows 10', window.navigator.pointerEnabled, window.navigator.msPointerEnabled) // Windows 10 true undefined
```
ractivejs/ractive-events-tap,ractivejs/ractive-events-tap