Merge pull request #90 from Bowman74/master

#89, Changed ImageButton to work with image types other than .png.
Fixes to iOS/Android WebHybrid

Fixes calls from an external web page, issue #86.

https://github.com/XForms/Xamarin-Forms-Labs/issues/86
Changed WP8 WebHybrid to support Local call

This will allow the WP8 callbacks to be called with the same redirect
command.
Fixes to the WebHybrid sample

All platforms now update the CanvasJS charts from the native controls.
Added the missing HTML references for WebHybrid
Merge pull request #14 from XForms/master

Merge from main.