[poppler] Poppler 0.50.0 released

[Albert Astals Cid]

Available from
http://poppler.freedesktop.org/poppler-0.50.0.tar.xz

Changes against 0.49.0 include:
core:
 * PSOutputDev: Fix PS conversion for some files. Bug #63963
 * Fix Outline parsing on broken documents. Bug #98732
 * Fix PDFDoc::saveIncrementalUpdate()'s detection of document being modified. Bug #96561
 * SplashOutputDev: Read softmask into memstrean in case of matte. Bug #97803
 * Bail out if Hints nBitsNumObjects or nBitsDiffGroupLength are greater than 32. Bug #94941
 * CairoOutputDev: initialize CairoOutputDev::antialias. Bug #98983
 * Fix crash when loading some thumbnails. Bug #97870

utils:
 * pdftoppm: Fix -tiff -gray/-mono incorrect output.
 * pdftops: add -passlevel1customcolor. Bug #97193

build system:
 * Default to libopenjpeg2 instead of libopenjpeg1

qt:
 * Support OCG state change links

glib:
 * Use g_slice_new0 for PopplerActionLayer. Bug #98786

Testing, patches and bug reports welcome.

Cheers,
  Albert