launchpad: Update config syntax, remove defaults

This patch updates the launchpad config to use XML attributes and
removes the built-in default configuration (which is only meaningful
for demo.run anyway).
base-linux: fix ELF dataspace execution

With this patch, if an ELF dataspace to be executed does not have a path
in the host file system, the dataspace content gets copied into a
temporary file whose path can be given to 'execve()'.

Fixes #879.
Noux: increase entrypoint stack size

Needed to run Noux built with -O0

Fixes #880.
Noux: register inherited file descriptors

With this patch, a Noux process registers all inherited open file
descriptors in its local libc file descriptor registry at program start.

Fixes #882.
libport: Fix download location of Mesa

Fixes #839
Put entry point at start of text segment / binary

Fixes #881.
Fix usb_storage.run for non-PC platforms

On non-PC platforms, the variable 'build' remains undefined, which lets
the 'build $build' step fail. Use the traditional 'build_components'
variable instead. As a further plus, this avoids multiple passes of the
build system.
base-hw: Pic::mask for rpi
dde_kit: Allow re-scheduling from timer handler

Prior this change, the attempt to re-schedule a timer from its timer
handler resulted in a clear '_pending' flag. This caused the timer event
to disappear from the scheduling queue without the handler being called
ever again. By resetting the '_pending' value before calling the hander,
we prevent a re-scheduled '_pending' flag to be cleared immediately
after calling the handler.
trace: Frontend for reading trace-buffer entries
trace: method for getting buffer-wrap count
trace: use new trace frontend in test-trace
attached_mmio: Support sub-page MMIO resources
dde_linux: Fix MAC validity check
Move generic platform_session parts to os/include

Both 'platform_session/capability.h' and 'platform_session/connection.h'
do not contain platform-specific information. By moving them from
'include/platform/imx53/platform_session/' to 'include/platform_session/',
this patch enables other platforms to reuse them.
nova: speed up cap selector allocation

Issue #485
Enable C++11 by default
nic bridge: connect to backend NIC on startup

After announcing the NIC service, the bridge connects to the driver to
ensure to see any incoming traffic in case the client itself only reacts
on connects from LAN (e.g., the netperf server).

Also, some styling issues were fixed.
netperf: enable netperf_bridge test on linux

Statically configured NIC bridge clients must be configured via
<policy...> nodes in the config. Otherwise, the bridge can't answer ARP
requests or route traffic.
ldso: fix compiler errors with C++11

The warning

  error: expected unqualified-id before ‘STRING_USERDEF’ token

was caused by a missing whitespace in 'extern "C"int'.