More fstapi.c updates from GTKWave.
More fstapi.c updates from GTKWave.

This syncs fstapi.c to the latest from GTKWave CVS. This cleans up
most of the issues. I still have two to track down, but I think they
are cppcheck bugs not fstapi.c deficiencies.

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