Film negative processing: first usable version. Only supports bayer raw files, thumbnails don't work

Added performance improvements suggested by heckflosse. Lowered median sampling step from 7 to 5 since calculation is now much faster.

Added support for Fuji X-Trans raw files.

Applied SSE2 patch provided by @heckflosse, improves performance in main processing loop.

Moved film negative processing stuff in its own compilation unit.

Code cleanup: removed redundant omp directives.

Added check for dead pixels, going above threshold after inversion. ST_BAYER only for now.

Reverted leftover hack in cropwindow.cc

rtgui/paramsedited.h

@@ -666,6 +666,15 @@ struct MetaDataParamsEdited {
     bool mode;
 };
 
+struct FilmNegativeParamsEdited {
+    bool enabled;
+    bool redExp;
+    bool greenExp;
+    bool blueExp;
+
+    bool isUnchanged() const;
+};
+
 struct ParamsEdited {
     GeneralParamsEdited general;
     ToneCurveParamsEdited toneCurve;
@@ -710,6 +719,7 @@ struct ParamsEdited {
     SoftLightParamsEdited softlight;
     DehazeParamsEdited dehaze;
     MetaDataParamsEdited metadata;
+    FilmNegativeParamsEdited filmNegative;
     bool exif;
     bool iptc;