Upgrade Veewee, lock down VMWare Tools version, upgrade kernel, make build process more robust.

We now download and use a specific, recent version of VMWare Tools (9.6.1-1378637).
This way the build will always succeed no matter which VMWare Fusion version the
user is using. This version of VMWare Tools also happens to work with kernel 3.8
without needing patches.
Add trademark mentions in the license
Fix VMWare Tools by removing DKMS.

Apparently the last attempt at upgrading VMWare Tools didn't work.
Although DKMS was able to successfully compile the VMWare Tools kernel
modules, the resulting modules don't work correctly. This time we use
vanilla VMWare Tools without DKMS. We use VMWare Tools's own method of
recompiling modules on kernel upgrades.

Also fix more build robustness issues and VirtualBox issues while we're
at it.
Enable host I/O cache in VMs.

These are development machines so we prefer performance over anything else.
Remove build-essential after kernel modules have been recompiled after a kernel upgrade.