The tests and modules were a little inconsistent; some would add the
lib directory to the includepath themselves, others expected the caller
to take care of it (usually test.pl).

Make it consistent: all tests should do it themselves, so that a plain
`prove' command can work.

Change-Id: I112dd0a1aa966404ab1a3c3b9467dcc83d1ddd0d
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Reviewed-by: Janne Anttila <janne.anttila@digia.com>
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>