Bugfix: adjusted text is too wide

With left-/rightaligned and centered text the resulting text was too wide in 
some cases. It looks as if the glue_spec that has shrinkability was replaced
by a glue_spec larger than that.
Default default from PlaceObject at Image/Barcode

Image and Barcode now take the width from the current width.
Two sample images for testing purpose

both are public domain

http://openclipart.org/detail/4112/simple-clouds-by-clue
http://openclipart.org/detail/179919/green-floral-by-vatanyraul-179919
sp: exit with status != 0 when sub process breaks

When the luatex subprocess exits with non-0 status we should return non-0 as
well.
Python script to generate dash docset, version

We bump the version to 1.99 to prepare for the 2.0 release. In due time we
can continue on the 1.7 branch.
LoadFontfile now uses system path as fallback

If a font is not found in the local search path, we fall back to the system wide
path (such as c:\Windows\Fonts or /Library/Fonts).
Better handling of cross platform font dir

We now have different files for windows/linux/mac.
Merge branch 'develop_v1.7' into develop

Better handling of cross platform font dir
LoadFontfile now uses system path as fallback
Bugfix: adjusted text is too wide