Fix handling of duplicate copy for local copies.

Do not use the imgid into the local-copy cache filename to have a single
original picture for all duplicate. This can save disk spaces.

Delete the local cache copy only when there is no more images (duplicate)
referencing it. Note that we also now properly delete cached XMP for
duplicate.

Note that the old scheme is kept for upward compatibility. So as long as
there is a local copy with the old naming scheme it will be used.
Usermanual update
colorin: fix film strip switching between raw and jpg

commit_params writes to the pipeline, the module params are _const_ in this
context (and it causes major threading issues and recursive drift of parameters
if violated, to say the least).
Fix D750 12-bit RAW format support (correct black/white level)
Fix _dt_sigsegv_handler when PTRACE restrictions are active (yama)
Starting with Ubuntu 10.10, PTRACE is limited to only direct descendants.

It is controlled by /proc/sys/kernel/yama/ptrace_scope
* if it is 0, then it is not needed
* if it is 1, then this IS needed
* else there is nothing we can do (no bt will be made)

FIXME: do we need to make child wait until prctl returns in main process?

Based on:
https://bugs.kde.org/show_bug.cgi?id=245529
https://breakpad.appspot.com/166001
https://wiki.ubuntu.com/Security/Features#ptrace
Merge pull request #714 from VictorLamoine/master

French translation of the entire usermanual
Define PATH_MAX as 4096 in case it is undefined.
Might fix build on Debian GNU/Hurd (i386)

https://buildd.debian.org/status/fetch.php?pkg=darktable&arch=hurd-i386&ver=1.4.2-1&stamp=1399195932
Merge pull request #716 from LebedevRI/fix-sigsegv-handler-when-yama

Fix _dt_sigsegv_handler when PTRACE restrictions are active (yama)
wb_presets: SONY RX100M2 (thanks to Matthew Harrison)
Lens IOP: Fix stack-buffer-overflow in lens_set()

READ of size 8 at 0x7fff4fa3b180 thread T0
    #0 0x7ff30bf19d87 in lens_set /home/lebedevri/darktable/src/iop/lens.c:1649

Also fixes Coverity CID1034336
Remove unused uncompressed modes
Merge pull request #704 from darktable-org/fix-dup-local-copy

Fix handling of duplicate copy for local copies.
Merge pull request #715 from cyr123/d750_rawfmts

Fix D750 12-bit RAW format support (correct black/white level)
wb_presets: Sony RX100M3 (thanks to Juliett09)
Flip IOP: modify_roi_in(): add sanity check
This "reverts" 3484731e3295f619bb99d41b3a12ba39e5c78919
Clipping IOP: modify_roi_in(): redo sanity check
This fixes following issue: when scalepixels iop is active, after activating c&r image is "cut in half" with the bottom half black.

NOTE: if there is no "sanity check.", there is a crash in dt_interpolation_resample
Lens IOP: do not use iwidth/iheight but buf_in.width/buf_in.height

iwidth/iheight is the size of original input buffer, which is correct
only if there is nothing in between changing the roi (like scalepixels)