- bugfix, correct ICC profileversion correctly

could extend IFD with missed tags automatically. The call of
  TIFFReWriteDirectory() adds a new(!) IFD at the end of the TIFF file.
  This is less dangerous, bot in very rare situations with very, very
  large TIFFs it could exceeds the 32bit offset value and fail.

- fixed printf-warnings

- fixed logical-or in cleantag checks
- removed superflous assertion
- fixed comment
- fixed some printf-warnings

- fixed logical bug in tag-range-check

- moved find_potential_IFD_offsets to subdir src/archeological_tools/
- fixed CMAKELists.txt for target all
- extended "soft" checks in find_potential_IFD_offsets
- improved output in find_potential_IFD_offsets

- added improved missed TIFF_INT64 workaround
- added compatibility flag for MingW

the corrected ICC profile is written directly (with low level functions)

- more descriptive output

- added more error handling code

- vim tabstop added

because the first call enhances size of TIFFs (the new IFD will be
  appended to the end). The TIFFWriteDirectory() instead replaces the
  old IFD with the new one. Because we do not enlarge the IFD (add
  more tags) it will be safe.

- uses part of codes from checkit_tiff for ICC handling, see
  https://github.com/SLUB-digitalpreservation/checkit_tiff

- removed superflous count variable

- renamed fixit/ to src/

strings, in rare case of missed constants, strdupa() is used
- fixed return type of TIFFGetRawTagListEntry() to tag_t
- fixed memleak in TIFFGetRawTagListEntry()