Incorrect cmd_build creation for VCS

[alina-andreevna]

1. top level module name is not provided in cmd_build line. This is potential problem for simulation when user top module is not matched than found in compile list by vcs
2. timescale parameter syntax in vcs timescale=1ns/1ps, not timescale 1ns/1ps. Also it should be part of cmd_build, not common cmd

[alina-andreevna]

I have a patch for this, but can not publish my branch:

ERROR: Permission to themperek/cocotb-test.git denied to alina-andreevna.
fatal: Could not read from remote repository.

Please make sure you have the correct access rights     
and the repository exists.

[themperek]

You need to fork this git repository and commit there and open pull request. Worst case province the code here.

[boryahlopunov]

Hi, ive made a fix for this issue.
please find it here
boryahlopunov#1

[themperek]

Close with #244