View lcov test coverage results on http://www.gnu.org/software/liquidwar6/coverage/src/lib/cns/index.html.
callback: handler function.
Installs a console handler.
Return value: none.
Polling function for console, must be called on a regular basis.
Return value: none.
line: line to add
Adds a line to the console history, won't add it if it's NULL or empty.
Return value: none.