Add support for the C++11 u and U encoding prefixes for char literals

"u" and "U" are new in C11 and C++11 for char literals.

Examples/test-suite/cpp11_raw_string_literals.i

@@ -47,6 +47,9 @@ wstring         aa =  L"Wide string";
 const char     *bb = u8"UTF-8 string";
 const char16_t *cc =  u"UTF-16 string";
 const char32_t *dd =  U"UTF-32 string";
+// New char literals
+char16_t uchar = u'a';
+char32_t Uchar = U'b';
 %}
 
 /* Raw string literals */

Source/Swig/scanner.c

@@ -938,6 +938,10 @@ static int look(Scanner *s) {
 	retract(s, 1);
 	state = 1000;
       }
+      else if (c == '\'') { /* Definitely u, U or L char */
+	retract(s, 1);
+	state = 77;
+      }
       else if (c == 'R') { /* Possibly CUSTOM DELIMITER u, U, L string */
 	state = 73;
       }