Add french keywords in .desktop.
(cherry picked from commit 43b63bc93f36df1b63c6eec8227f875d2d1c5e6a)
tiff output: set sample format for 8bit and 16bit too

DT tiff makes enfuse complain about missing info:
Warning: no TIFFTAG_SAMPLEFORMAT or TIFFTAG_DATATYPE, guessing pixeltype 'UINT16'.

Setting the sample format for 8bit and 16bit cases fixes this.
(cherry picked from commit 8add5fbf30461ad474f23b89e29ffd37c96c3d3a)
Add italian keywords in .desktop

Based on PR 471
(cherry picked from commit 2788dc0854180a129b635a5c2698dd5fdda686eb)
Add German keywords to .desktop file
(cherry picked from commit 99ca2e44a6be9bb7f19122fb519a9a10c226e581)
tiff output: several fixes

- add TIFFTAG_SAMPLESPERPIXEL tag to avoid possible confusion in readers
- cast all values to their correct type as documented in
  http://www.awaresystems.be/imaging/tiff/tifftags/search.html
  this should fix BE archs as writing a uint16_t written as 32 or 64bit
  value would have always resulted in a 0 value being interpreted if
  varargs use the stack
- fix a bug where last strip was never written for 32bit
  (spotted w/ enfuse)
- factored the stripe allocation logic
- make 8/16/32 bit codepath similar enough to just differ by the used
  pointer type
- add proper error path for OOM conditions and tif opening failure

NB: enfuse still creates pure white images from dt float tiff :-(
(cherry picked from commit 573ef4134a6e7bfc25b31f76063c210e0df77f2f)