Fix broken examples

[JayFoxRox]

We had reports, that most example code does not work (crashes a56 if I remember correctly). It is not known what causes this.

[examples]$ make
cpp -Uicon caltone.a56 > tmp.a56
../a56 -o caltone.out tmp.a56 > caltone.lis
/bin/sh: line 1: 13393 Segmentation fault      (core dumped) ../a56 -o caltone.out tmp.a56 > caltone.lis
make: *** [Makefile:21: caltone.omf] Error 139

a56 should always provide meaningful output instead of just crashing.

We should identify those cases, fix the examples and fix a56.
Because this could be a lengthy task, it would already be good if someone reviewed all examples and created an issue for each broken one, unless a common issue can be identified (which can be discussed here).