Add initial build tests

Build tests should be a set of various targets etc that in the end uses as
many features as possible in Bob to prevent regression. It is not aimed as a
performance test. Only the smallest set of files to cover each aspect should
be created.
Add Qt4 application to build tests

Initial Qt4 application to test uic, moc and dependencies etc. Especially the
generated files must in some cases be created before source files can be
compiled. (More files need to added later).
Add extra ui (widgets) files to Qt4 build test

More ui-files will enable a more complex parallel tree when uic must be
completed before compilation starts.
Use rpath=TGTDIR for all tests

Having TGTDIR as part of the rpath (while testing) makes it a lot simpler to
execute the applications, else LD_LIBRARY_PATH must be set to include
TGTDIR. Which is of course forgotten when a new shell is started.
Extend glob-expansion for all SRCS-variables

Cherry-picked from master
Add more ui-files and source to build tests

More files and more dependencies makes the build tests more complicated and
exercises the dependency setup better. Qt ui-files must be completed before
compilation starts. Mocing headers must also be completed before compilation
but can only be moced after the ui-processes is complete etc.
Merge branch 'buildtests'

Merge first batch of basic build tests. A executable, a library and a Qt4 gui
application with some inter-dependencies. Multiple ui-files and moc-files for
the Qt4 application does not seem to breakable so far.