vendor_lib/verilab/svlib_dpi.so should be built by the Makefiles, not stored in the repo.

A compiled shared-object for the SVLIB from Verilabs is stored in this repo at vendor_lib/verilab/svlib_dpi.so. The shared-object should not be in the repo, so we need to:

• Remove vendor_lib/verilab/svlib_dpi.so fromthis repo.
• Add to the appropriate .gitignore.
• Check (and potentially update) the Makefile(s) to rebuilt this shared-object from scratch.
• Check (and potentially update) the Makefile(s) to ensure the clean_all target deletes the shared-object.