hdf5_der

Merge pull request #173 in HDFFV/hdf5 from ~DEROBINS/hdf5_der:gitignore to develop

Updated .gitignore to be more manageable and future-proof.

* commit '1aa2373b2e1a651bec507dcb14a89b51815a972c':
  Simplified .gitignore by using patterns.
  Added src/H5config.h.in~ to .gitignore.