REST API status and collection pagination

I've added an endpoint to RestIndex called /status. This gives the client app some basic information about it being properly authenticated or not. It helps for sanity checking every once in a while. Also, the client app displays your fullname, instead of your email address, that comes from the eperson. I don't think I need the status to pass back the token, the app stores that locally (and uses for each request).

Also, I couldn't understand the logic for tokenHolder setting the eperson's password. We shouldn't allow the user to change their password, so I took out that set password line. 

I've also added some log.info statements, just so that things that REST API is doing, get logged. User login, logout...

I've reverted/fixed the /collections pagination iterator. It would be better to use dspace-api Collection.findAll(context, limit, offset). Kevin has fixed that method with metadata4all (for oracle), so it should be assumed that it is safe to use. DSpace/DSpace[master] has metadataforall now. Your PR could either be Rebased against DSpace/DSpace[master], or just ignore that, and wait for it to get merged (I'm thinking Monday).