added Sherlock function

Realised that I actually have to find nodes regularly so moved it out
of the <k> context and made it into a function
added functionality and test for 'b' and 'f'

* wrote the functions
* altered the way messages are created
  -> globalMessageCount now starts at 0 and its incremented ++global*
meaning it reflects the number of active messages.
* i dun goofed with the implementation of ‘a’