New utility for managing volatile class members

Fixes #1025
XML generator and test

Fixes #1019
Add Attached_rom_dataspace::update

This patch enhances the 'Attached_rom_dataspace' utility to support
dynamic updates of ROM modules.
New 'os/attached_dataspace.h' utility

The new Attached_dataspace complements the existing Attached_*
utilities with a simple version that can be used with any kind of
dataspaces. It may be even useful as a common base type for the other
variants. For example, this patch simplifies Attached_rom_dataspace
and removes the Terminal::Client::Io_buffer.
util/string.h: String::operator ==
Dynamic ROM service for automated testing
Use filename as default label for ROM connections

By assigning the file name as label, we may become able to remove the
filename argument in the future by just interpreting the last part of
the label as filename. By keeping only the label, we won't need to
consider conditional routing (via <if-arg>) based on session arguments
other than the label anymore.
Infrastructure for posting status reports

This commit introduces the "Report" session interface and a simple
service to forward reports to the LOG service.

Fixes #1026
nitpicker: Report pointer position
Service for reflecting reports as ROM modules

Issue #1026
base: New Genode::Deallocator interface

Splitting the new Genode::Deallocator interface from the former
Genode::Allocator interface enables us to restrict the accessible
operations for code that is only supposed to release memory, but not
perform any allocations.

Additionally, this patch introduces variants of the 'new' operator
that takes a reference (as opposed to a pointer) to a Genode::Allocator
as argument.
Xml_node::Attribute::value_size accessor
Scout: Add DroidSans-Bold10 font as tff
Minimalistic decorator for window system
Simple desktop environment (WiP)
base: optional length argument for String::String
Add 'operator *' to os/volatile_object.h

This operator is needed when we want to create a reference to (the
content of) a volatile object.
Accessors for Xml_node utility

This patch adds accessors to obtain the buffer of an attribute value,
which is useful to avoid the copying-out of such information by
maintaining pointers into the XML string as meta data.
Generic resource monitor (WiP)