netperf: use Genode specific alarm timer

Fixes #1021
hello: fix quota value and integration of timer

Fixes #1028.
noux: add block device file system

Access to a block session is provided by using the block file system.
By specifying the label, each block session request can be routed to
the proper block session provider:

! <fstab>
! 	...
! 	<dir name="dev">
! 		<block name="blkdev0" label="block_session_0" />
! 	</dir>
! 	...
! </fstab>

In addition to this file system, support for the DIOCGMEDIASIZE ioctl
request was added. This request is used by FreeBSD and therefore our
libc to query the size of the block device in bytes.

Fixes #1010.
noux: add e2fsprogs-v1.42.9 package

Fixes #1029.
libc: add support for sysconf(_SC_PAGESIZE)

Fixes #1029.
create_iso: give hint on missing tools

Fixes #627.
block: use new server framework in block drivers

As a side effect, the entrypoints in the USB driver are merged into one thread.

Fixes #1027
run: instruct 'exec' to ignore stderr output

Unless '-ignorestderr' is set on 'exec' in expect, any output on stderr
is interpreted as execution failure. In this case, 'create_iso' logs
some diagnostics but does not fail.
Arora: fix the demo launchpad configuration

This patch adapts the launchpad configuration of the Nitpicker plugin demo
to the current launchpad config syntax.

Fixes #1018.
Fix memory leak in Gallium EGL driver

With this patch, the reference count of the textures created in
'Surface::_validate()' gets decreased in the '~Surface()' destructor.

Fixes #1012.
Arora: add gallium.lib.so boot module

QtGui depends on gallium now, so gallium.lib.so needs to be available as
boot module.

Fixes #992.
terminal_echo.run: Adjust timer quota
Length and capacity accessors for Genode::String
tool/fix_include_ifndef: consider license header
Move nitpicker_gfx/geometry.h to util/geometry.h

This patch makes nitpicker's geometry utilities available for the use
by other programs. Thereby, the 'Point', 'Area', and 'Rect' classes
have become templates that take the coordinate type and distance type
as arguments.
Add demo/include/util/dither_matrix.h

This patch moves a repeatedly used dithering matrix from the scout
source code to a public header to share it across programs.
Remove nitpicker_gfx/miscmath.h
Move nitpicker_gfx/color.h to util/color.h
Remove nitpicker_gfx/nitpicker_types.h
Generalization of nitpicker's graphics backend

This patch re-arranges nitpicker's graphics backend in a more modular
and expandable way. Generalized versions of the 'Canvas',
'Chunky_canvas', and 'Pixel_*' classes have been moved to
'os/include/util/' and 'os/include/os'. The only remaining parts that
are specific to nitpicker's needs are a few drawing functions, each
located in a distinct header at 'os/include/nitpicker_gfx/'.