Handle correctly filter on the Roundabout loop sequences

[romaintailhurat]

Consider this questionnaire:

When trying to generate, i get a nasty Pogues2DDI error:

Eno generation error: An error was occured during the POGUES_XML_GOTO_2_ITE transformation. 
A sequence of more than one item is not allowed as the first argument of fn:number() 
(@position="16", @position="24", @position="16", ...) : 
Error in :/xslt/pre-processing/pogues-xml/goto-2-if-then-else.xsl ; SystemID: ; Line#: 478; Column#: 7

Indeed, there is a problem because the Roundabout component cannot be included in the filter starting on S2.

Could the problem be solved by allowing that inclusion?