AES-NI use in VirtualBox 5.0

[birdie]

1) Does VirtualBox use AES-NI instructions? Make sure you do.
2) Please, add a warning for people whose CPUs lack AES-NI instructions because without hardware assisted acceleration AES encryption/decryption can be very taxing (there are quite a lot of people out there running Intel Celerons and Pentiums).

[aeichner]

We do use AES-NI where available. Have to check how much effort it is to implement the warning in case AES-NI is not available.