Add sanity check to AVL tree, fix #597
Turn 'Timer::Session' into asynchronous interface

The 'Timer::Session::msleep' function is one of the last occurrences of
long-blocking RPC calls. Synchronous blocking RPC interfaces turned out
to be constant source of trouble and code complexity. I.e., a timer
client that also wants to respond to non-timer events was forced to be a
multi-threaded process. This patch replaces the blocking 'msleep' call
by a mechanism for programming timeouts and receiving wakeup signals in
an asynchronous fashion. Thereby signals originating from the timer can
be handled along with signals from other signal sources by a single
thread.

The changed interface has been tested on Linux, L4/Fiasco, OKL4, NOVA,
L4ka::Pistachio, Codezero, Fiasco.OC, and hw_pbxa9. Furthermore, this
patch adds the timer test to autopilot.

Fixes #1
timer: Build platform-specific parts as lib

By using the build system's library-selection mechanism instead of many
timer targets with different 'REQUIRES' declarations, this patch reduces
the noise of the build system. For all platforms, the target at
'os/src/drivers/timer' is built. The target, in turn, depends on a
'timer' library, which is platform-specific. The various library
description files are located under 'os/lib/mk/<platform>'. The common
bits are contained in 'os/lib/mk/timer.inc'.
Adaptation to Timer::Session change
Turn 'platform_env.h' into a private header

This patch removes 'platform_env.h' from the public API headers because
this header was not part of the API anyway.
Remove 'Native_lock' type from 'native_types.h'
Unify 'ipc.h' and 'ipc_generic.h' across platforms

The distinction between 'ipc.h' and 'ipc_generic.h' is no more. The only
use case for platform-specific extensions of the IPC support was the
marshalling of capabilities. However, this case is accommodated by a
function interface ('_marshal_capability', '_unmarshal_capability'). By
moving the implementation of these functions from the headers into the
respective ipc libraries, we can abandon the platform-specific 'ipc.h'
headers.
pistachio: Remove dead code
base-hw: Adaptation to signal API change

This patch is an interim fix for building base-hw until the signal
implementation is revisited on this platform.
xvfb: Adaptation to timer and framebuffer changes
base-host: Build fixes
Increase timeout of signal.run test
moon.run: Increase quota of 'test-moon'

With the use of the new timer interface, each timer client uses signals.
Hence, programs that have not used signals before will consume slightly
more quota. This is the case for the moon test (triggered on foc_x64_64
only).
Merge base libraries into a single library

This patch simplifies the way of how Genode's base libraries are
organized. Originally, the base API was implemented in the form of many
small libraries such as 'thread', 'env', 'server', etc. Most of them
used to consist of only a small number of files. Because those libraries
are incorporated in any build, the checking of their inter-dependencies
made the build process more verbose than desired. Also, the number of
libraries and their roles (core only, non-core only, shared by both core
and non-core) were not easy to capture.

Hereby, the base libraries have been reduced to the following few
libraries:

- startup.mk contains the startup code for normal Genode processes.
  On some platform, core is able to use the library as well.
- base-common.mk contains the parts of the base library that are
  identical by core and non-core processes.
- base.mk contains the complete base API implementation for non-core
  processes

Consequently, the 'LIBS' declaration in 'target.mk' files becomes
simpler as well. In the most simple case, only the 'base' library must
be mentioned.

Fixes #18
Update example configurations

With the change of the Timer::Session interface, all scenarios that use
the timer use core's SIGNAL service. So we need to route sessions
accordingly.

In addition to the adaptation to the changed timer, this patch removes
some stale examples that predate the run tool and are no longer used.
Remove base-mb platform

This base platform is no longer maintained.

For supporting the Microblaze CPU in the future, we might consider
integrating support for this architecture into base-hw. Currently
though, there does not seem to be any demand for it.
Remove os/config

This patch moves the os/config examples to their respective run scripts,
removes some of them, and moves the priority example to the src/init
directory (where other examples are located).

Additionally, this patch adapts the OKL4-specific priority.run test to
the recent changes of the timer interface.
core: preserve more memory

core needs to preserve more memory when built with -O0 for the 64-bit
'linux_x86' platform

Fixes #653.
usb_drv: prevent recursive signal dispatch

Fixes #649.
timer & foc: use KIP->clock as curr_time