*8895* Include PKP PLN plugin in OJS stable

Has been tested and works - basically for all of these, if the status passed in is true I do an OR against the field to set the flag and in the case of a false I flip the flag and AND it against the field to unset it (preserving the state of the rest of the field). The more generic get/setStatus() above (which I'm commenting as such now) are useful here but less so outside the class - the intention was to use these get/sets to get/set/toggle individual bits.