Encodes data using base64 algorithm
@author Tyler Akins (http://rumkin.com)
@param {String} input
@returns {String}
@memberOf emmet.base64
function(input) {
			var output = [];
			var chr1, chr2, chr3, enc1, enc2, enc3, enc4, cdp1, cdp2, cdp3;
			var i = 0, il = input.length, b64 = chars;

			while (i < il) {

				cdp1 = input.charCodeAt(i++);
				cdp2 = input.charCodeAt(i++);
				cdp3 = input.charCodeAt(i++);

				chr1 = cdp1 & 0xff;
				chr2 = cdp2 & 0xff;
				chr3 = cdp3 & 0xff;

				enc1 = chr1 >> 2;
				enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
				enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
				enc4 = chr3 & 63;

				if (isNaN(cdp2)) {
					enc3 = enc4 = 64;
				} else if (isNaN(cdp3)) {
					enc4 = 64;
				}

				output.push(b64.charAt(enc1) + b64.charAt(enc2) + b64.charAt(enc3) + b64.charAt(enc4));
			}

			return output.join('');
		}