Fix file not being closed in case of error in with block

robofish.io.File.__exit__ overrides h5py.File.__exit__. This is important when File is used as a context manager. In case that there is an exception being raised from within the with block, robofish.io.File.__exit__ was not closing the file. Instead of closing the file explicitly in robofish.io.File.__exit__, a call to super().__exit__ should always happen to close the file.