Fix path error
Add JPEG support
Remove native view pinning

 - Maintain references to children views inside of javascript rather
   than native code so the garbage collector can decide when to free the
   views
 - Also free the subview array when destroying a view
Use pthread wrapper
Implement JPEG base64 writer
Improve image cache debug log
Fix huge etag database load times by truncating
Add limit to etag database write size to avoid huge write latency
Merge pull request #35 from gameclosure/fix-native-view-leak

Remove native view pinning