Initial commit of version 5.0.0
gitignore: add generated files to the ignore list
changelog: move to archived-changelog

The changelog has been last updated in 2008, so it looks to be pretty
much irrelevant.
configure: Fixed check of Python library version.

Debian and Ubuntu also have python-2.7.pc file in python-dev package, so this
one is the common point.
debian: Always run autogen.sh in rules.
travis: Added Travis YML configuration file.