No longer prefix verilog package identifiers with veryl project names

[nblei]

This is in order to deal with the issue I raised #324

I am not sure entirely why module and package names are prefixed with project names --- perhaps because verilog has no real module system or namespace system. If that's the goal, then emitter.rs should be changed to also prefix package identifiers in scoped_identifier.

[dalance]

I intended that the prefix is used to realize package namespace.
So scoped_identifier should be prefixed by package identifier.

[nblei]

OK Dalance, I will withdraw this pull request because it seems like you have a better solution in mind.