Header parser should accept uppercase letters.

lib/parser.js

@@ -1,7 +1,7 @@
 'use strict';
 
-var TOKEN    = /([!#\$%&'\*\+\-\.\^_`\|~0-9a-z]+)/,
-    NOTOKEN  = /([^!#\$%&'\*\+\-\.\^_`\|~0-9a-z])/g,
+var TOKEN    = /([!#\$%&'\*\+\-\.\^_`\|~0-9A-Za-z]+)/,
+    NOTOKEN  = /([^!#\$%&'\*\+\-\.\^_`\|~0-9A-Za-z])/g,
     QUOTED   = /"((?:\\[\x00-\x7f]|[^\x00-\x08\x0a-\x1f\x7f"])*)"/,
     PARAM    = new RegExp(TOKEN.source + '(?:=(?:' + TOKEN.source + '|' + QUOTED.source + '))?'),
     EXT      = new RegExp(TOKEN.source + '(?: *; *' + PARAM.source + ')*', 'g'),