22: Minus function 

not fully supported by SPARQL join yet

Task-Url: http://github.com/plt-tud/r43ples/issues/issue/22
reformat code

#22: Minus function 



Task-Url: http://github.com/plt-tud/r43ples/issues/issue/22
resolves #22: Minus function 

works now also with SPARQL join

Task-Url: http://github.com/plt-tud/r43ples/issues/issue/22
update README