gensio 3.0.1 and ser2net 4.6.6 released

It's been a while since the 3.0.0 release of gensio. Nothing
earth-shattering here, a few bug fixes:

• Problems with IPv6 compatibility and running without a fully working network.

• The permissions of the PTY were not set correctly with gtlsshd.

• Some issues building under MSYS2 were fixed.

And some enhancements:

• A "chardelay" gensio is added. This is basically the same as the
  Nagle algorithm in TCP, but it works on other things, like UDP and
  relpkt, to make transfer more efficient on those.

• You can use "gsh" instead of "gtlssh" for a shorter name.

• Lots of little documentation updates.

For ser2net, this release fixes a couple of minor bugs, but is primarily
here to have a ser2net windows executable that works with the current
gensio executable. The executables are only for Windows, and
unfortunately, must be aligned. If you build it, you can still pretty
much mix arbitrary versions of ser2net and gensio.

So this Windows executable works with the gensio 3.0.1 Windows
executable only.