Swig/Python: Fixed pointer bug when setting signal min and max.
Swig/Python: Corrected min and max property lengths in testvector.py
Fixed bug passing lo_arg arrays for storing vector property values.
Remove unsigned changes for >= 0 (clang warning)
Add swig/copywhich.sh to the dist.
swig: Use alloca() to reserve stack variables used in typemaps.

Otherwise, swig sometimes places variables inside scopes, and
retaining pointers to these variables causes problems.