Fix search_varfb_instance_decl to be able to find variables and FB when only given an identifier.
Fix handling of FB calls in stage3.
Start handling of function invocations in stage3.
IEC 61131-3 Annex F Examples (informative)
This directory contains example code take from:
Annex F of Draft 2nd edition of the IEC 61131-3 standard (1998)
"PROGRAMMABLE CONTROLLERS - PROGRAMMING LANGUAGES"