Add quote special form

src/main.c

@@ -19,10 +19,9 @@ int main(int argc, const char **argv) {
     ucl_state_put(state, "lambda", ucl_special_create(ucl_special_lambda));
     ucl_state_put(state, "setq", ucl_special_create(ucl_special_setq));
     ucl_state_put(state, "progn", ucl_special_create(ucl_special_progn));
+    ucl_state_put(state, "quote", ucl_special_create(ucl_special_quote));
 
     // TODO:
-    //   - progn
-    //   - quote
     //   - iteration
 
     ucl_state_put(state, "print", ucl_builtin_create(ucl_builtin_print));