Events hooks fix

[GoogleCodeExporter]

I have downloaded this project to use in my app. And I have found out that 
events(onLoad, onComplete and onError) are not working properly. Java methods 
are not invoked.

After debugging, I have found the problem and here is the fix:
In WebcamImpl.java file change   private native JavaScriptObject create** 
methods to the following code:

  private native JavaScriptObject createOnErrorHook() /*-{
    var _this = this;
    return function(result) {
        _this.@com.logikas.gwt.webcam.client.WebcamImpl::fireErrorEvent(Ljava/lang/String;)(result);
    };
  }-*/;

  private native JavaScriptObject createOnLoadHook() /*-{
    var _this = this;
    return function() {
        _this.@com.logikas.gwt.webcam.client.WebcamImpl::fireLoadEvent()();
    };
  }-*/;

  private native JavaScriptObject createOnCompleteHook() /*-{
    var _this = this;
    return function(result) {
        _this.@com.logikas.gwt.webcam.client.WebcamImpl::fireCompleteEvent(Ljava/lang/String;)(result);
    };
  }-*/;

The problem was that during event, this object was different from the moment of 
function creation. Therefore it was needed to store an exact object, for which 
the function would be invoked.

Original issue reported on code.google.com by guerrill...@gmail.com on 13 Nov 2013 at 2:14