dependencies: bumped http servers, including gunicorn. gunicorn==19.7.1 waitress==1.0.2

dependencies: bumped gevent to 1.2.2 together with greenlet to 0.4.12

dependencies: bumped test libraries. pytest==3.1.2 py==1.4.34 pytest-cov==2.5.1 pytest-sugar==0.8.0 pytest-runner==2.11.1 pytest-profiling==1.2.6

dependencies: bumped venusian to 1.1.0

dependencies: bumped ptyprocess to 0.5.2

dependencies: bumped pathlib2 to 2.3.0 - adds scandir dependency

nix: bumped version to 4.9.0

release: Bump version 4.8.0 to 4.9.0

release: merge back stable branch into default

Added tag v4.8.0 for changeset 0b7c790b726f