Update unicode function to allow for ligatures

The code uses this unicode function in two places; first to read the font and create a map of glyphs, and secondly to parse a string into glyphs.

Fixes #7 (closed)

src/Controllers/LockupsController.php

@@ -8,10 +8,10 @@ use \SvgGenerator as SVG;
 
 class LockupsController extends Controller {
 
-	const LOCKUP_VERSION = '1.4';
+	const LOCKUP_VERSION = '1.5';
 
 	private static function checkTextFieldLength($params, $field, $max_length) {
-		if (strlen($params[$field]) > $max_length) {
+		if (mb_strlen($params[$field]) > $max_length) {
 			self::flashNotice(parent::NOTICE_LEVEL_ERROR, 'Invalid Text', ucwords(implode(' ',explode('_', $field))) . ' must be ' . $max_length . ' characters or fewer.');
 			return FALSE;
 		}