package: some additions to setup.py and docs conf

- Module nix.info defines author, version, contact etc.
- Use nix.info in setup.py
- Additional definitions in setup.py such as descriptio and classifiers
- Use nix.info in docs/sources/conf.py
setup.py: use pkg-config for compiler flags
setup.py: set version to 0.9.2
setup.py: parse info from nix/info.py
info.py: set version to 0.9.3
setup.py: catch exception in pkg_config()
info.py: set version to 0.9.4
setup.py: failsafe pkg_config()
setup.py: failsafe pkg_config()

Conflicts:
	debian/changelog
	nix/info.py
	setup.py
Merge pull request #47 from stoewer/master

Package related changes

LGTM