Updates to kNet.

[Jukka Jylänki]

Some new things related to kNet:

- There is now a buildbot at http://clb.demon.fi:8115/waterfall
- A good feature update from Stinkfist
https://github.com/juj/kNet/pull/12 was merged, allowing specifying on
the command line what build options are enabled.
- So far the default has been to have boost _enabled_, and Qt
disabled when building (without any cmake command line parameters).
- In the future, I want to change the default to require no extra
dependencies, so the default will change to have both boost and Qt
_disabled_ if no command line parameters are given.
- As preventive measures, Tundra kNet build should probably not
assume either as default, but always explicitly pass
-DUSE_BOOST=TRUE/FALSE in Tundra deps kNet cmake line to choose which
one is needed.

Jukka