lwip: add checksum options to 'lwipopts.h'

This patch adds some of lwip's checksum calculation options to the
Genode-specific 'lwiptops.h' configuration file. The checksum calculations
are enabled by default.

Fixes #868.
nic_bridge: cache card's MAC address (Fixes #869)
Increase default NIC session's queue size (fix #870)
core: explicitly throw Out_of_metadata

In case there is not enough quota left to create the trace buffer
or trace policy dataspace throw Out_of_metadata explicitly instead
of rethrowing the Ram_session::Quota_exceeded exception. Now one
can catch Trace::Out_of_metadata exception in a client application.

In addition fix Allocator_guard::withdraw() checks because this
method does not throw any exceptions and a failed withdrawal goes
unoticed.

Fixes #871.
CPU affinity configuration fixes

- if no affinity was set for a new thread before calling
  Cpu_session::start(), the CPU session's affinity gets set for this
  thread
- documentation fix: <affinity_space> -> <affinity-space>

Fixes #873.
lwip: fix thread reset value in 'sys_arch_unprotect()'

Fixes #866.
usb_drv: initialize '_tx_alloc' variable

Fixes #867.
tool/run: Let grep_output strip colors from output
lwip: remove redundant function declaration
pingpong: fix compiler warnings
lwip.run: Increase quote of test-lwip_httpsrv

Adaptation to the recent increase of the NIC session quota.
ldso.run: Do not match escape sequences

Color escape sequences do not need to be considered when using
grep_output in run scripts.
init: Do not abort on invalid (re-)configurations
tool/run: Whitespace
Noux GDB: resolve '..' in run script

If the path of a Genode source file (as extracted from the binary test
application) contains a part like '/a/b/../' where '/a' exists, but '/a/b'
does not exist anymore, 'tar' complains. With this patch, the run script
normalizes the path before calling 'tar'.

Fixes #875.
GDB monitor: move GDB commands into separate file

This patch moves the GDB commands to set a breakpoint in the 'main()'
function into a separate file that can be included from other run scripts.

Fixes #876.
run: make 'is_qemu_available' return false for Linux

Fixes #862.