Some examples had syntax errors; those have been fixed. Additionally,
I added a simple example with a while loop. It does not contain a proper
post-condition either, which might be interesting as well (as the
program might be able to handle those properly too).

This change allows us to calculate program paths from all programs (as
long as they don't contain any try-catch). Using this, we should be able
to calculate ALL wlps for the programs. However, the checks are not
complete for the whole program, as only program paths up to a certain
length are checked. Any further program paths might say that the program
is (in)correct and give a different result.