I was fed up to cd into the tests/conform or tests/interactive directories
to launch a specific test. Now, with the power the abs_ variants of
builddir and srcdir we can run specific test from any directory.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2159
Allow using the BindConstraint to bind width and height of a source
actor.
Also, add a test for the BindConstraint showing all types of usages
for this constraint class.
