Add 'make test' target to run tests

[godbyk]

[Incidentally, qstest looks quite useful. I've been meaning to find a testing framework for my LaTeX cocde for quite a while now. I'll have to explore qstest some more.]

[wspr]

I haven't looked too much into it either. Unless it can parse the log file, though, we're not going to be able to add any of the \pkg@warning-type tests to the test suite.

I'm going to assign this bug to you :)

[godbyk]

No problem!

[godbyk]

test target was added in commit 690e225.