This file has been deleted, but references to it in the build remain,
causing `debuild` to fail.

debian/copyright{,.in}: Adopt from Debian's upload candidate, being DEP-5 compliant and up-to-date for 3.5.99.3.

 Fixes ArcticaProject/nx-libs#2.

debian/copyright{,.in}: Adopt from Debian's upload candidate, being DEP-5 compliant and up-to-date for 3.5.99.3.

 Fixes ArcticaProject/nx-libs#2.

 Fixes ArcticaProject/nx-libs#188.

use system libXext instead

This commit removes TextCompressor class references from ClientCache
and ServerCache as it's no longer used after removing old protocol's
compatibility code from nxcomp. It also removes the attribute textCache
from both classes as it's no longer used either.

Finally the header and source files associated with the TextCompressor
class are also deleted and removed from the compilation process.

Refs: ArcticaProject/nx-libs#108

This commit removes obsolete compatibility files whose components were
only used to handle compatibility with old protocol versions that are
no longer supported.

Refs: ArcticaProject/nx-libs#108