Handle all valid delimeters for SO:box

[gothub]

The SPARQL queries that extract schema.org bounding box coordinates from a geo.box property only handle single spaces, but need to handle and combination of commas and spaces. Here are some possibilities for box:

• "-28.09816 -32.95731 41.00 1.71098"
• "-28.09816,-32.95731 41.00, 1.71098"
• "-28.09816,-32.95731 41.00,1.71098"
• "-28.09816, -32.95731 41.00, 1.71098"