rtrclient: add missing port argument in SSH usage example

The port number argument was missing in the SSH example of rtrclient's
usage output.

(Thanks to David Mandelberg for reporting)
cmake: add UseMultiArch cmake module

Source: https://raw.github.com/OPM/opm-upscaling/master/cmake/Modules/UseMultiArch.cmake

The cmake module fixes wrong multiarch installation paths when cmake is
called from debhelper
cmake: build documentation by default

if doxygen is present, build the documentation in the all target
cmake: install documentation to share/doc/rtrlib/
cmake: move rtrclient install statement to tools/CMakeLists.txt

All cmake statement related to files in tools should be in
tools/CmakeLists.txt
This commit moves the cmake install install statement for the rtrclient
tools to tools/CmakeLists.txt.
debian: add debian packaging files
transport: remove const modifier from tr_{ssh,tcp}_config members

Remove the const modifier from tr_tcp_config and tr_ssh_config elements.
The const modifier for the elements made it hard to follow
the common declaration-after-statement style.
It also stands in the way when the variable was created and the
assignment should be done in a different scope, e.g. in the branch of an
if-statement
rtrclient: fix segfault, access to out of scope tr_config members

A segfault happened in rtrclient shortly after start.
The ssh_config and tcp_config variables were
defined in the block scope of an if-statement. In this block the memory
address of the config structs were passed to the transport init
functions.
When the config were accessed in a later state of the program again, the
scope of the config variables was expired.

(Thanks to David Mandelberg and Michael Mester for reporting and
locating the cause of the segfault)
rtrclient: increase polling period from 1 to 30 seconds

Polling the server every 30 second is sufficient.
README: remove release notes

The release notes for future releases will be managed via github.
Docu: Replacement of draft-ietf-sidr-rpki-rtr and draft-ietf-sidr-pfx-validate by RFC 6810 and RFC 6811.
rtrlib/pfx/lpfst/lpfst/lpfst-pfx.h: update docu
debian: remove unused variable from rules file
debian: don't run "make test" during package creation

The "make test" run failed while package creation  because the rtrlib
shared library couldn't be found.
I suppose it's because of the required -DCMAKE_SKIP_RPATH=True cmake
option in the debian rules file.
For now it's sufficient if the test are run manually and not
automatically when a debian package is created.
debian: change my debian maintainer mail address to git@...

I used a different mail addresses for the debian changelog entries and
the debian/control maintainer entry. This caused
changelog-should-mention-nmu lintian warnings.
debian: release debian package 0.2.3-1
Merge branch 'master' into develop

Conflicts:
	tools/rtrclient.c