allowed for data URIs in the src of the pdf viewer for dynamic pdf viewing

with this patch, it's possible to use ng-pdfviewer interactively by changing the source of the dom element to different data uris. we can use the dom element like this: <pdfviewer ng-src="{{pdfContent}}" on-page-load='pageLoaded(page,total)' id="viewer"></pdfviewer>
and then feed the data uri into pdfContent. that even allows to use a user selected pdf file to be displayed immediately, using html5 filereader: 

$scope.pdfUpload = function(input)
        {
            var reader = new FileReader();
            reader.onloadend = function () {
                var data = this.result;
                $scope.$apply(function () {  $scope.pdfContent = $sce.trustAsResourceUrl(data); });
            };
            reader.readAsDataURL(input.files[0]);
        };

with <input type="file" id="file" name="file" ng-model="pdfFile" onchange="angular.element(this).scope().pdfUpload(this)" />