function loadScript(sPath, sFilename) {
		return new Promise(function (resolve, reject) {
			var script = document.createElement('script');
			script.async = true;
			script.src = sPath + sFilename;
			script.addEventListener('load', resolve);
			script.addEventListener('error', function () {
				return reject('Error loading script: ' + sFilename);
			});
			script.addEventListener('abort', function () {
				return reject(sFilename + ' Script loading aborted.');
			});
			document.head.appendChild(script);
		});
	}
Loads a <code>javascript</code> file.

@param {string} sPath The root path
@param {string} sFilename File to be loaded
@returns {Promise} A promise which resolves when the script is loaded
@private