Port of the Illumos fully automated testsuite

This is just the initial pull request - it still needs a lot of work, but at least it work mostly/somewhat.

Currently, about half of the tests succeeds:
```
Results Summary
FAIL     236
SKIP     395
PASS     242
```
A large part of the tests is skipped, and this is mostly because the test setup script fails (usually because it does/calls something that isn't available on Linux yet).

I still need to make sure I don't get false negatives (as in 'it really is a FAIL and not a problem with the port' which is "somewhat likely").

At the moment, there's a lot of commits (I'm trying to rebase the commits in a way that I can send it to Illumos for possible inclusion there). I will also force-push to the branch every now and then, without any warning. So take care if/when testing this.


!!!!!! WARNING !!!!!
There is a couple of gotchas about the test suite! The most dangerous one is that many of the test script doesn't expect existing pools on the system. So it will try to delete every pool it can find!
!!!!!! WARNING !!!!!

How to run: Just run <code>./autogen.sh && ./configure</code> (no need to do the build - it will use commands already installed). Then just run <code>make test</code>.

There are a couple of things that needs to be setup first, so the <code>test</code> target will check your system to make sure everything is a-ok and tell you what's wrong.

The thing I've been unable to check is that the test user needs to be able to run sudo without password.

See the Makefile for more information (I'll see if I can write a README.test eventually). Some of this needs to be rewritten eventually, but I'm holding of on that until I'm satisfied with the port.

Closes: #1534