Changed cow.js model to remove array

This makes searching documents easier as you no longer have to loop
through all the arrays to find a particular value.
Added the /cattle/herds/:herd route
Added route to display individual cow
Created a post route to update records
Merge branch 'development'
Added a delete route to remove a cow from the database
Added initial medicine routes
Added individual medicine route
Added the edit medicine root
added delete medicine route
Merge branch 'development'