How to get and save a file from a list to another list in another site by REST API

gistfile1.js

function getParam ( name ) {
	if ( name = ( new RegExp ( '[?&]' + encodeURIComponent ( name ) + '=([^&]*)' ) ).exec ( location.search ) )
		return decodeURIComponent ( name [ 1 ] );

	return "";
}

function copySelectedProposal ( selectedProposal, dstParam, succeededCallback, failedCallback ) {

	if ( selectedProposal == null )
		return;

	var x = {
		absUrl : _spPageContextInfo.siteAbsoluteUrl,
		relUrl : _spPageContextInfo.webServerRelativeUrl,
		dst : dstParam,
		proposal : selectedProposal
	};

	x.filename = selectedProposal.substring ( selectedProposal.lastIndexOf ( "/" ) + 1 );
	x.srcUrl = _.str.sprintf ( "%(absUrl)s/_api/web/getFileByServerRelativeUrl('%(proposal)s')/$value", x );
	x.dstUrl = _.str.sprintf ( "%(absUrl)s/%(dst)s/_api/web/getFolderByServerRelativeUrl('%(relUrl)s/%(dst)s/LibUploadedFiles')/Files/add(url='%(filename)s',overwrite=true)", x );

	console.debug ( x );

	$.getScript ( _spPageContextInfo.scriptbase + "/SP.RequestExecutor.js", function ( ) {
		var executor = new SP.RequestExecutor ( x.absUrl );

		var info = {
			url : x.srcUrl,
			method : "GET",
			binaryStringResponseBody : true,
			success : function ( data ) {
				var result = data.body;

				var destInfo = {
					url : x.dstUrl,
					method : "POST",
					headers : {
						"Accept" : "application/json; odata=verbose",
						"X-RequestDigest" : $ ( "#__REQUESTDIGEST" ).val ( )
					},
					contentType : "application/json;odata=verbose",
					binaryStringRequestBody : true,
					body : result,
					success : function ( bla ) {
						alert ( "Success! Your file was uploaded to SharePoint." );
					},
					error : function ( mah ) {
						alert ( "Oooooops... it looks like something went wrong uploading your file." );
					}
				};
				executor.executeAsync ( destInfo );

			},
			error : function ( err ) {
				console.debug ( err );
				failedCallback ( );
			}
		};

		executor.executeAsync ( info );
	} );
}