(bug 25325) fix hiding bot edits

I added support for 'wlshow' parameter, which allows user
to decide if to include or exclude bot/minor/anon/patrolled
edits from feed watchlist.

Plus: I bound the params checkup and params' descriptions with
ApiQueryWatchlist (Yurik's suggestions).

Change-Id: Idab489fc017dcf226ea39f2f1766e06064e4ec0a
Merge "(bug 25325) fix hiding bot edits"