plusargs removal

[Hooligan-0]

Plusargs section has been removed on some cores but not for all. Is it because some users use old versions of fusesoc or this sections can be cleaned everywhere ?

[olofk]

The rationale here has been to replace the plusargs with parameters when I push new versions of a core, so that the current .core files are backwards compatible. I'm getting a bit annoyed myself by these messages though, and FuseSoC 1.4 has been out for a while now so there might be a case for removing them