Initial commit of ADB class (work in progress)

This is basically a copy of AccessDB.m with initial modifications to
turn it into a class. Further work is required.
NOP functino auth: gone.
Make more properties available to others, i.e. session_handling
Turning helper functions into class members (1)
function .serverconfig works
.serverconfig: dlSize is also a bytefield
Small typo ...
Renamed class-internal self-use to "self". Is more obvious ...
Counter deletion is now mandatory on construction.

This practically renders the counter file obsolete: #22