UnresolvedType: fix JVM signature conversion

Fixes #211. Previously, '?' was not converted to '*' in
UnresolvedType.nameToSignature, but kept as-is. That is why - falsely -
it was necessary to handle the '?' case in UnresolvedType.forSignature
at all, reading this kind of bogus signature and creating a type for it
in TypeFactory.createTypeFromSignature. This, ironically, led to correct
JVM generic type signatures containing '*' not being handled at all.

The conversion should now work correctly both ways.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

org.aspectj.matcher/src/main/java/org/aspectj/weaver/TypeFactory.java

@@ -152,7 +152,7 @@ public static UnresolvedType createTypeFromSignature(String signature) {
 				return new UnresolvedType(signature, signatureErasure, typeParams);
 			}
 			// can't replace above with convertSigToType - leads to stackoverflow
-		} else if ((firstChar == '?' || firstChar == '*') && signature.length()==1) {
+		} else if (firstChar == '*' && signature.length()==1) {
 			return WildcardedUnresolvedType.QUESTIONMARK;
 		} else if (firstChar == '+') {
 			// ? extends ...

org.aspectj.matcher/src/main/java/org/aspectj/weaver/UnresolvedType.java

@@ -418,7 +418,7 @@ public static UnresolvedType forSignature(String signature) {
 			return TypeFactory.createTypeFromSignature(signature);
 		case '-':
 			return TypeFactory.createTypeFromSignature(signature);
-		case '?':
+		case '*':
 			return TypeFactory.createTypeFromSignature(signature);
 		case 'T':
 			return TypeFactory.createTypeFromSignature(signature);
@@ -746,7 +746,7 @@ private static String nameToSignature(String name) {
 				return "C";
 			}
 			if (name.equals("?")) {
-				return name;
+				return "*";
 			}
 		}
 		if (len == 0) {