Rename trnio routines

- Rename all routines from trnio.h to gmx_trr_*, and replace trn with
  trr also in the implementation.  Use more comprehensible names than
  read_htrn().
- Fix one missing gmx_trr_close() in eigio.c.
- Get rid of contrib/anaf.c, which was some cut-down version of gmx dump.

Change-Id: Id4ea14e83ce14089bbdf0e672f15531cf0f22e61