Update French translation.
VNG4 for Bayer sensors

This brings the Bayer-specific code from dcraw into linear and VNG
interpolate, so that it can work as VNG4 for Bayer images.

also misc. cleanups:
- lin_interpolate(): don't need to offset by roi_out x/y which is set to
  0,0 by process()
- vng_interpolate(): alloc a single memory range for both buffers
Merge pull request #627 from dtorop/vng4

VNG4 for Bayer sensors
demosaic: properly capitalize AMaZE since other are capitalized too
demosaic: indicate VNG4 is slow
Fix (r3) a regression in flip iop legacy params handling

Basic Idea: if history stack has flip iop with orientation != -1,
then this history stack was, either:
1) created before regression (and had gone through legacy_params, which never produces -1), and we need to fix it!
or
2) created after regression (by manual changes to flip iop, and we should not fix it

Q: Is there a way to differentiate between these two?