collect: fix crash in case of non-valid utf8 database entries

g_markup_escape_text() does not tolerate invalid utf8 strings.
we need to to fix those upfront.
Italian translation updated
imageio: hard block extentions handled by rawspeed again

most if not all cameras should work now, the only exception
being missing panasonic aspect ratio's, which should be easy
enough to quickly add.
imageio: _blacklisted_ext now protects libraw from xtrans rafs
Merge pull request #633 from bartokk/master

Italian translation updated
update pt_BR master
Merge pull request #635 from guitorri/master

update pt_BR master
Try to add sane defaults to an empty XDG_DATA_DIRS
Merge pull request #632 from upegelow/collect_utf8_fix

collect: fix crash in case of non-valid utf8 database entries
Fix help message for picasa module

What the user needs to copy is the code given in the page, not the URL
rawspeed: implement RawImageData::getDataUncropped()
Bauhaus: add dt_bauhaus_slider_set_boundaries
Histogram: replace dt_iop_roi_t with new dt_histogram_roi_t
Needed preparations for loading of uncropped, unscaled (B/W) raw images
dt_imageio_open_rawspeed(): break everything! Stop cropping.
rawprepare: new IOP, no-op (passthrough)
rawprepare: allow tiling

FIXME: verify this!
rawprepare: border cropping for raw mosaic buffers
Mipmap cache: prepare for border cropping for (downsampled) floating point buffers
rawprepare: border cropping for floating point buffers