Updated comments and minor syntax change
Handle filters as strings

Now the module can handle filters that are strings. If the filter is a string, the module emits a server event that has the following format:

"userActions:<filter value>"

The event data is sent in the following parameters:
 - link
 - crudRole
 - the callback function

The callback function will be called from the custom script
or another module with the following parameters:
 - err: an error that appeared in the custom script/another module
 - computedFilter: an object containing the query passed to mongo
 - appendIdAndTp: if `false`, _id and _tp fields will NOT be set
 to the final filter
Merge branch 'master' of github.com:IonicaBizau/user-actions
Minor comment updates
Updated dev changelog