major debian packaging refactoring for python3

 - additional binary package for python3
 - also outsource all test related things to "..-dbg" package
 - avoid lintian hardening warnings (additional linker flags)
Merge branch 'master' into deb_python3
Merge branch 'master' into deb_python3
deb: adapt control fields (depends/recommends etc.)
Merge branch 'master' into deb_python3
minor plotting workaround for older matplotlib versions
deb: add missing build dependencies
deb: further adjustments to build dependencies
deb: pybuild is only available for newer Debuntu releases, so we need to
keep old build instructions for old ones..
deb: further adjustments to buildsystem switch
deb: further build adjustments
deb: update ubuntu releases
deb packaging: adjust Debuntu releases (remove lucid, ..)
deb packaging: fix #558 again
deb packaging: minor fix for control file
deb packaging: add missing dep on python-future in old build system
control file
deb packaging: avoid conflicts between py2/py3 console scripts, separate
naming for python 3 (e.g. obspy3-runtests)

prevents problems in packaging (pseudo-randomly sometimes ending up with python2
interpreter, sometimes python3 interpreter hard coded into executable
scripts)
deb packaging: try to fix scripts on python3
deb packaging: fix for previous commit
deb packaging: add missing files