message: Show tried paths in ResourceNotFound error message
diff: @@ -161,6 +161,7 @@ impl Filesystem {
  /// Opens the given path and returns the resulting `File`
  /// in read-only mode.
  pub fn open<P: AsRef<path::Path>>(&mut self, path: P) -> GameResult<File> {
  + let mut tried: Vec<path::PathBuf> = vec![];
  // Look in resource directory
  let pathref: &path::Path = path.as_ref();
  @@ -169,6 +170,7 @@ impl Filesystem {
  let f = fs::File::open(pathbuf)?;
  return Ok(File::FSFile(f));
  }
  + tried.push(pathbuf.clone());
  // Look in resources.zip
  if let Some(ref mut zipfile) = self.resource_zip {
  @@ -177,6 +179,7 @@ impl Filesystem {
  let name = pathref.to_str().ok_or(GameError::UnknownError(errmsg))?;
  let f = zipfile.by_name(name)?;
  return Ok(File::ZipFile(f));
  + //TODO: add path to zip + path within zip to `tried`
  }
  // Look in user directory
  @@ -185,10 +188,11 @@ impl Filesystem {
  let f = fs::File::open(pathbuf)?;
  return Ok(File::FSFile(f));
  }
  + tried.push(pathbuf.clone());
  // Welp, can't find it.
  - let errmessage = convenient_path_to_str(pathref)?;
  - Err(GameError::ResourceNotFound(String::from(errmessage)))
  + let errmessage = format!("{:?}; checked in {:?}", convenient_path_to_str(pathref)?, tried);
  + Err(GameError::ResourceNotFound(errmessage))
  }
  /// Opens a file in the user directory with the given `std::fs::OpenOptions`.
  