Work on issue #13, increasing the connection count for daqd/nds1.

This addresses the issue by expanding the size of the bitmask.
* Replace the 'int' bitmask with a generic structure.  This allows the
type system to help us find all the places it is used.
* Replace direct bitmask manipulation with member functions to increase
local readability.
* Allow the new bitmask structure to have an increased capacity that can
be set (at compile time).
* Add unit tests to new bitmask code.
* Add test code to look at nds1 load.