Improve Readme and code stylign

* Alphabetic options added into Readme.md
* Add empty space after 'if' in new option validation

README.md

@@ -34,7 +34,19 @@ srs({length: 256}, function(err, sr) {
 	console.log(sr);
 });
 ```
+### Options: alphabetic
 
+Optionally, you can specify a 'alphabetic' option to get a alphabetical chars only.
+
+```javascript
+// sync
+var result = srs({alphabetic: true});
+
+// async
+srs({alphabetic: true}, function(err, sr) {
+	console.log(sr);
+});
+```
 ## Error handling
 
 

lib/secure-random-string.js

@@ -26,9 +26,10 @@ function srs(options, cb) {
 
 	function _finish (buf) {
 		var string = buf.toString('base64');
-		if (alphanumeric === true){
+		if (alphanumeric === true) {
 			string = string.replace(/[\W_]+/g,'');
-		}else{
+		}
+		else {
 			string = string.replace(/\//g,'_').replace(/\+/g,'-');
 		}
 		return string.substr(0, length);