Fix evaluation of ! expressions.
Add optional target suffix for the binary / installation folder.

This is mainly intended to be used for building snapshot binaries that
are able to install in parallel to a release build. E.g. by using the
parameter "SUFFIX=-nightly" for qmake, the target binary will be called
openscad-nightly and the resource base folder /usr/share/openscad-nightly.
Merge pull request #1053 from openscad/install-suffix

Add optional target suffix for the binary / installation folder.
Fix make install with INSTALL_ROOT set, e.g. used by Debian package build.
Update .desktop file to include the install SUFFIX.
Fix install target for translation files.
Fix translation file install target when running qmake on clean source.
Bumped Qt to 5.3.2
Minor testcase tweak
#1055 added testcase
#1055 Doc: Clarify sanitized polygons
Bugfix: 2D scale or mirror sometimes caused flipped normals which caused larger issues downstream. Fixes #1055
#1054 Fixed memory leak
Disable vertical refresh syncing.
removed fixed fixme
Added more nullspace tests
Disabled less useful test
Handle a bunch of nullspace corner cases. Fixes #1029
Merge pull request #1060 from openscad/qglformat-patch

Disable vertical refresh syncing.
Try to detect if compiling with a 32bit or 64bit compiler.