Fix for Genymotion: "Unable to load VirtualBox engine"

Recently I tried out Genymotion, a new emulator for Android that is based on virtual machines inside of VirtualBox. Genymotion easily beats the standard Android emulator hands down: it boots much faster and runs super slick and smooth.
It was very easy to set up and create devices, too. However, after the next reboot of OSX Mavericks, I couldn't start the machines anymore and instead got this:

Unable to load VirtualBox engine.
Make sure that you have installed it correctly before starting Genymotion.
For more information refer to: https://cloud.genymotion.com/page/faq/#vbox

It turns out that this is due to missing kernel extensions that VirtualBox requires to operate which are not automatically loaded. The following command will load them:

sudo /Library/StartupItems/VirtualBox/VirtualBox restart

After running the command Genymotion will be able to start devices again. However, this is will only solve the problem once, I am still looking for a permanent fix.