* New: In designflow.surelog, support for the Synlig Surelog/UHDM plugin
for Yosys.
* Fix: In designflow.svase, remove the transient file "slang-args.txt".
* Change: In designflow.yosys, remove the direct SystemVerilog support
that is delegated to Surelog and just load the resulting UHDM.
Merge with yosysnp and automatically detect if we can load the
Python plugin or go through a script.
Jean-Paul Chaput