Cleanup - let's make IDEs more useful

http://phpdoc.org/docs/latest/references/phpdoc/types.html

If IDEs have many warnings, we don't look at them.
Let's minimize the number of warnings, and make them useful again.

* Some function docs fixes
* Removed unused $iwprefixes var in ApiQuerySearch.php
* declared private $blockStatusByUid in SpecialActiveusers
* declared private $repo in UploadFromChunks

Change-Id: Ifd20f78b168b9a913fdb8d89dc26a76a173b1c29
Merge "Cleanup - let's make IDEs more useful"