This patch is to make search work again after the new SQL optimisations,
by removing some of the optimisations when searching is used.
Optimisation of search is left for some future work.
The whole base is indeed transfered from MySQL to PHP, which is not
good.
Big effect (on speed and memory), but few changes :-)
Drastically reduced the number of SQL requests needed (from 233 down to
8 to load the home page with my own data set = 140 feeds in 15
categories).
Drastically reduced the amount of data transferred from MySQL to PHP.