While easy to use, auto-starting threads generates problems when more
complicated initialization takes place.

Rather than making auto-start optional (as Guy suggested), remove it
completely, to keep the API simple.

Use thread::start() to start a thread.  Unstarted threads ignore wakeups
until started.

Just like fat the test isn't wired up yet until we have the infrastructure
for it.

It's done since i uses as a increasing input for the data that resides in
a single byte.
In addition, make sure that the read buffer is initialize to zero and not
the target data we wish it to be.

Found while testing readonly disk property

reduce the verbosity

Running tests is now done by editing the command line in build.mak

and verify their content. The image is been run over but the content
is restored after each write

With virtio we must use dynamic allocation for the correctness of
virt_to_phys

The tests themselves didn't change and all the changes their are just
changes of namespace usage and variable movement.

the vtest class) and running them one after the other.
It moves the test code outside of loader.cc

Run 2 threads, one allocated mem, the other deletes the allocation.

osv:
     147 NanoTime
     574 context switch

fedora:
     322 NanoTime
    2484 context switch

(nanoseconds, on kvm, on my laptop)

One test so far: java.lang.System.nanoTime()

We're only about 500% slower than native.