fix(templates): Allow single quote characters in literals (#326)

Single quotes are valid in uris, so we do not want to break
users of this library who may have single quotes in their templates.

src/URITemplate.js

@@ -137,7 +137,7 @@
   // pattern to verify variable name integrity
   URITemplate.VARIABLE_NAME_PATTERN = /[^a-zA-Z0-9%_.]/;
   // pattern to verify literal integrity
-  URITemplate.LITERAL_PATTERN = /[<>{}'"`^| \\]/;
+  URITemplate.LITERAL_PATTERN = /[<>{}"`^| \\]/;
 
   // expand parsed expression (expression, not template!)
   URITemplate.expand = function(expression, data) {