[Mediawiki-api] Behaviour when no titles specified

[Max Semenik]

Currently, when you specify not titles parameter for queries that
require it, such as http://en.wikipedia.org/w/api.php?action=query&prop=info
you get an empty result set:

<?xml version="1.0" encoding="utf-8"?>
<api />

Wouldn't it be more beneficial to return error in such cases, or at
least to provide a notice that there is noting to query from?

-- 
  Max Semenik ([[User:MaxSem]])