gitignore: Don't ignore the top-level docs/ dir

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Bump versions to 0.2.0-SNAPSHOT.

There will be no 0.1.3, so bump the version up to 0.2.0-SNAPSHOT.

Signed-off-by: Gergely Nagy <algernon@balabit.hu>