Check char::from_u32 for invalid code point

fix #75

src/lib.rs

@@ -640,7 +640,7 @@ impl Ini {
         let key = section_key!(section);
         self.sections.remove(&key)
     }
-    
+
     /// Delete the key from the section, return the value if key exists or None
     pub fn delete_from<S>(&mut self, section: Option<S>, key: &str) -> Option<String>
         where S: Into<String>
@@ -1133,7 +1133,12 @@ impl<'a> Parser<'a> {
                             }
                             let r = u32::from_str_radix(&code[..], 16);
                             match r {
-                                Ok(c) => result.push(char::from_u32(c).unwrap()),
+                                Ok(c) => match char::from_u32(c) {
+                                    Some(c) => result.push(c),
+                                    None => {
+                                        return self.error("unknown character in \\xHH form");
+                                    }
+                                },
                                 Err(_) => return self.error("unknown character in \\xHH form"),
                             }
                         }