VBOX: Introducing a basic graphics application for vboxwrapper based on HTML rendering. Basic plumbing is done.

TODO:
* Add vbox job elements to point to various URLs for various states. (running/suspended/not running)
* Add window timer to poll for shared memory changes
* Exit if running in screen saver mode and keyboard/mouse activity is detected.

VBOX: Make the service install scenario work again.

VBOX: last_checkpoint_cpu_time != last_checkpoint_elapsed_time.  When to checkpoint is based on elapsed time, what we reported to boinc is the cpu time.  Keep track of both values.

VBOX: Introduce the notion of Virtualbox COM namespaces. We currently support VirtualBox 4.2 and VirtualBox 4.3.

When the file is detected, the wrapper will call boinc_temporary_exit() and restart the VM at a later date.

VBOX: Move common code to VBOX_BASE class, VBOX_VM derives from it by extending virtual functions calling Vboxmanage or Native API functions.  Use ATL on Windows to wrap COM Objects and data types.

When the file is detected, the wrapper will call boinc_temporary_exit() and restart the VM at a later date.

TODO: Refactor how command line options and vbox_job.xml options are handled.  This was a ugly hack.

VBOX: Set the network configuration at VM creation time.  set_network_access() is called whenever the network is suspended or resumed.  It'll cause multiple DHCP requests to be spawned on a network resume.

All vbox_job.xml to specify ranges of port forwardings,
and whether the access to the host ports is remote or local.
This is to support MPI for Rytis.

Notes:
- the existing feature (pf_guest_port) is used only for web graphics.
  The host port is always dynamically assigned;
  there's no reason to have <pf_host_port>; I removed it from the doc.
  There's no reason to write the host port to a file; I removed that.
- The new feature is only for fixed host ports.
- The checkpoint file can stay the way it is.

Signed-off-by: Carlos Aguado Sanchez <carlos.aguado@epfl.ch>

This commit adds two extra options:
- enable_cache_disk
- cache_disk_filename

This allows to attach a cache disk image to extend the storage
needs initially provided by the OS image.

In context-based systems such as uCernVM, this image can be
used to store the local cache of artifacs coming from CVMFS.

Note this image is attached without further checking on the content
and is entirely up to the main OS to make good use of it.

Signed-off-by: Carlos Aguado Sanchez <carlos.aguado@epfl.ch>

This commit allows to attach an ISO9660 image to a vbox VM
from a well-known file. The purpose is to enable the dynamic
configuration of the VM in first boot so that the volunteer VM
can be kept generic. This process is otherwise widely known as
contextualization of virtual machines.

The actual content of the ISO9660 image is application dependent
and outside the scope of this implementation.

Signed-off-by: Carlos Aguado Sanchez <carlos.aguado@epfl.ch>

Add logic in wrapper to maintain and checkpoint total runtime.
Also vboxwrapper: slight refactor.

Note: we often use "elapsed time" where we mean "runtime".
Should use the latter.

pause for 60 seconds before exiting, and don't read trigger file.
For ATLAS@home.  Undo when they update their VM.

When it's finished, the VM app can write a file of a given name
(specified in vbox_job.xml) in the shared dir.
This file can optionally contain an exit code and stderr text.
If vboxwrapper finds this file, it cleans up the VM and calls boinc_finish().
This works around a problem where the VM doesn't exit properly
and the task hangs forever.