do not build gettext or glib2 by default. fix glib2.pri to find system version.
fix spaces.
do not suggest the 'time saver' of only opencsg or cgal build, too confusing
fix issue #705 by using MXE's mingw-*-pkgconfig instead of system
Catch exceptions caused by parsing invalid double values (fixes #706).
Merge pull request #712 from openscad/number-fix

Catch exceptions caused by parsing invalid double values (fixes #706).
add quotes to line 80 to prevent diagnostics
Merge branch 'master' into unstable

Conflicts:
	README.md
	scripts/uni-build-dependencies.sh
	scripts/uni-get-dependencies.sh