Improve -n and -N VSM handling.

This makes sure that VSM_Name always has something sensible to return.
API documentation fixes.
Add a VUT.name desc string of the currently open VSM context.
Use VUT.name as descriptive name of VSM context.

Fixes issue where a 2nd VSM context is used to get the current name,
not taking any -n/-N arguments into account
Long line fix
Display EOF upon hitting end of input
Stop updating counters after hitting EOF