Start the restructuring of the source code for KChart 2.0.

This commit removes the data editor and saves it in the new directory attic/. We also copy all the files that were affected by this commit to the same directory for future reference.

The idea is that once we have sucked all useful code out of the classes in attic/ we will make a garage sale, er I mean we will remove it and all its contents and be left with a new pristine KChart baby that will lead to 2.0.