Doc: Increase version to v0.2.1 and update CHANGES

Increase the version file to indicate that this is a maintenance branch for
v0.2.0. Add already finished fixes into CHANGES file.
Deb: Add configuration for package creation

Add packaging configuration for Debian package and update various files to
reflect version increase.

The version number reads 0.2.0+0.3.0 to indicate this is developement version of
the package. Version should be manually changed to 0.3.0 when package is
released.
Release: Update documentation and version to indicate release
Merge branch v0.2.0 maintanence branch

Conflicts:
	CHANGES
	configure.ac