FCxtrans parameter fixes

- highlights: don't need to +6 row & col params, they will never be
  negative

- demosaic and hotpixels: row & col params can be -1 or -2; note this
  in comments as the rationale for +6 then modulo 6

- row/col params for FCxtrans() should be const int, not size_t:
  allows for negative numbers (to not break demosaic/hotpixels), is
  still large enough, matches type used by callers, and enforces const

- demosaic: use row & col instead of y & x to match FC() and other
  FCxtrans()
update "supported file formats" in manual

RAW was listed twice as a format, make first instance into RAF.
create HDR does not work with X-Trans sensors
note X-Trans CFA alignment is different than Bayer

It may well be better for X-Trans to conform to the Bayer example, so
note this difference. This is especially true as, once the image
rotation happens in the flip IOP, it will no longer be necessary to
determine the shift of the X-Trans CFA depending on image rotation.
eliminate X-Trans linear demosaic from UI

Linear is fast, but not that good quality. The actual
xtrans_lin_interpolate() code needs to remain, as
xtrans_vng_interpolate() uses it.

Conflicts:
	doc/usermanual/darkroom/modules/basic/demosaic.xml
	src/iop/demosaic.c
PR 584: no pre-flipping needed for X-Trans CFA

Now that flip happens in IOP flip rather than loading, don't need to
flip the X-Trans matrix on load. Also, as per that PR, make constants
unsigned for special "9" filter signifying an X-Trans matrix.
Clip & Rotate IOP: fix regression in aspect ratio calculation

Was introduced by 0a3a5574fdc9b33792fda4d29be8445545ea8a92
Make sure the current history is written before pasting some others.

This fix the following issue:
1. open an image on darkroom
2. apply some iop
3. copy and paste some iop from another image

At this stage the changes done in 2 are lost. This commit fix this issue.
Merge pull request #614 from darktable-org/path-clone-offset

Use 0.02f as offset for creating source path.
Updated Dutch translation
Merge pull request #618 from MRIG/master

Updated Dutch translation
Update French translation.
Update French translation.
Write history only when in darkroom mode.

Continued work ofr 6ebf97c.
Fix issue when duplicating image from lighttable.
presets: sort presets by name after writeprotect sorting
Italian translation updated
Merge pull request #620 from bartokk/master

Italian translation updated
rawspeed: nikon 1 j4 experimental support
vignette: decent lomo preset
Merge pull request #588 from dtorop/xtrans2

support X-Trans sensor raw files