Fix, the try/finally node needs to forwards the "needsFrame" to its children.

* This corrects Issue#140.
Fix, there was no code generation for exception matches as expressions.

* These can result from optimization. We do not yet analyse well if they
  might have side effects, and default to assuming so.

* Found by compile library test in matplotlib.
New hotfix release.
Merge branch 'hotfix/0.5.2.1'