Ensure built Python is picked up for Cython build
Add CURL version to add_sb_package(...) call
Ensure HDF5 build used correct version of zlib
zlib => ZLIB so find_package(...) will work

Also include the zlib version
Add CURL version to add_sb_package(...) call

Also make SYSTEM the default
add_sb_package => add_sb_python_package for numpy
Add version to add_sb_package(...) call for wget

Also make default SYSTEM