CheckCast after MapGet if not primitive

Required for Type assertion, else a 'Object is not assignable to X' will follow

JavaBytecodeCompiler/src/main/java/org/openzen/zenscript/javabytecode/compiler/JavaExpressionVisitor.java

 				javaWriter.invokeInterface(MAP_GET);
 
 				type.valueType.type.accept(type.valueType, unboxingTypeVisitor);
+				if(!CompilerUtils.isPrimitive(type.valueType.type)) {
+					javaWriter.checkCast(context.getType(type.valueType));
+				}
 				break;
 			}
 			case ASSOC_INDEXSET: