Rewrite the article class using enums, only one get/set function is needed now.

Rewrite the article class using enums, only one get/set function is needed now.
So far we only read/write singular. But support is there for plural and dual.
Deprecated old constructor with arguments, but leave it for now, since porting will take some time.
This breaks compability with articles in kvtml2 docs!
Port parley to use that stuff.

svn path=/trunk/KDE/kdeedu/libkdeedu/; revision=715352