Fix for GitHub issue #30 : failed assertion in eval_tree.cc
Fix for GitHub issue #30 : failed assertion in eval_tree.cc

The root cause was the constant propagation done during elaboration
of a multiply operation, which didn't check for mixed real/logic
expressions.

CastMi/iverilog,themperek/iverilog,themperek/iverilog,themperek/iverilog,CastMi/iverilog,CastMi/iverilog