Piping to idp results in segfault

[Bart Bogaerts]

when trying to execute commands like cat solution.idp idpinstance.idp | idp, I get a segfault. Valgrind doesn't tell me where to search for it

[Broes De Cat]

cat ~/idp/tests/mx/simplemx/doubleneg.idp | ./install/bin/idp -e "print(modelexpand(T,S)[1])" works perfectly for me on the current master.

[Bart Bogaerts]

Fixed piping to idp

When piping to IDP, one of the "active" files is NULL. When checking for new includes, we shouldn"t try to deref this.

This fixes #346

→ <<cset e2eeefe36b1e>>

[Broes De Cat]

Fixed piping to idp

When piping to IDP, one of the "active" files is NULL. When checking for new includes, we shouldn"t try to deref this.

This fixes #346

→ <<cset 47484b68c774>>

[Joachim Jansen]

Fixed piping to idp

When piping to IDP, one of the "active" files is NULL. When checking for new includes, we shouldn"t try to deref this.

This fixes #346

→ <<cset 7e67afc9c27a>>