OSX: rework the mess that was start script

(cherry picked from commit 5dd992918e990aed168b06cc2eaa790afbe0dfd5)
Cleanup the NX3000 decoding code from dcraw

(cherry picked from commit 055b85898bb92d7a0054904f69e8781e390dfb83)
Remove duplicate code.

(cherry picked from commit b53329b48ca9aae5395f8d5a3501b8747691e151)
darkroom: scale processed view with window size

(cherry picked from commit e72625e06da05e4abd7ce9e606498239e7a58ef8)
Hide mouse in slideshow mode

(cherry picked from commit a7d755a675b5cbcf2fb709c6dbf57b7e3ba74955)
spots: fix icons states bug 10216

(cherry picked from commit e899f1ddebc64b5d24b7f955f9c29c9030faf712)
Add support for the Pentax *istDL

(cherry picked from commit ce6ea86a044603eaf6782710dbef990e03bf12f2)
Show option for txt overlay in prefs

(cherry picked from commit bc6475556eedd4917bb90a6a154824408b0646c7)
Exposure IOP: enable soft boundaries for black

(cherry picked from commit f787994f342dc23417610fb63f8ff3543673668a)
Merge remote-tracking branch 'upstream/darktable-1.6.x' into darktable-1.6.x