Version 0.11

Major breaking change, reduced scope of package and eliminated object-oriented aspects.
The new nexpr command does not require narray objects, it works on regular Tcl variables.
Additionally, the nset/nreplace command has an optional "= $expr" syntax, borrowed from the "@" method in the old narray class.
Table datastructure and object oriented framework will be in a different package.
This package is all about the ND-list paradigm (everything is an ND-list), so it works on raw Tcl values.