going back to UNRELEASED
bump standards
GPL-3.0+ canonical is GPL-3+
debian/README.debian will be installed by default
add python to Recommends
default boost version is enough now
add parallel support for dh
remove export DH_OPTIONS
use --sourcedirectory and --builddirectory for dh

  this also allowed me to make more clean debian/rules and
  no need to override_dh_auto_build.
we don't need CFLAGS and CXXFLAGS anymore

  also removal of $(BUILD_DIR) is not necessary. dh is dealing it just
  fine
remove dpkg-dev build dependency
add python support
replace dh-python with python