* PLZ.pm: new fmt FMT_EXT

  This format can be extended without limits by using key=val fields.

  New methods get_extfield and get_extfields to access the new fields.

  get_street_type was changed to use get_extfield.

  The projected (and never implemented) FILE_STRYPE and LOOK_STRTYPE
  fields were removed.

  PLZ::Multi constructor has a new option -usefmtext to support the
  new FMT_EXT format.

  New test script t/plzext.t.
* PLZ.pm: no more FMT_*

  The FMT_NORMAL format was never really used, so I removed it. With
  its removal, all the other FMT_* could also go, because these were
  basically compatible (only additional fields were missing).

  In the conversion process, I also changed an open() to use lexical
  filehandles. So the minimum perl version is now 5.6.0.
* oldname2plz: new script for creating a PLZ.pm-compatible file with
  oldname -> newname mapping
* data/Makefile: new target oldnames
* the new data/oldnames file
* PLZ::Result

  Also added AsObjects=>1 support in some PLZ methods (look,
  look_loop, look_loop_best).

  With new test script plzresult.t
* more PLZ::Result functionality:
  * clone
  * set_name/citypart/zip
  * combined_elem_to_string_form (same functionality as the PLZ.pm
    counterpart, but operating on the object)
  * as_arrayref method
* PLZ::combine is now using PLZ::Result objects by default

  But there's a compatibility mode for the old array-based objects.
Merge branch 'new-plz-fmt'
* MANIFEST update
* data update (oldnames is now also part of .modified)
* replay_accesslog: more normalizations for session ids
* convert_orig_to_bbd: handling new directive ignore_oldname_file: yes

  This directive is used to not create an "oldname" directive in the
  strassen file, and consequently won't appear in the oldnames file.
  Mainly used for streets which are only partially renamed, and where
  a "oldname" hint is not really necessary.
* more deps needed for bbbike-temp-blockings-optimized.pl target

  check_bbbike_temp_blockings does checks using check_points and
  check_neighbour against strassen and other files.
* data update (u.a. Auerbachstr., changes in Westpark,
  using new ignore_oldname_file directive...)