debugging: Let typeDump() show UDT's namespace
debugging: Let symbDump() use typeDump() so UDT namespaces are shown
debugging: Remove unnecessary abs() in typeDump()
astBuildBranch(): Remove unnecessary subtype check

We know dtype=FB_DATATYPE_STRUCT, so the subtype will always be <> NULL.
parser: Update statement count after end-of-statement, not earlier

This fixes up some error reporting issues, where the "expected EOL" error
could be shown despite another error having been shown for the same
statement already. Normally the error module tries to prevent reporting
multiple errors in the same statement, but due to the statement counter
being updated too earlier, it failed.
GFX commands: Accept UDTs with cast() overload as target/source image