making smaller & faster report

["Stanislav Slusny" <slusnys gmail com>]

Hello,

I forgot to send report this Monday - sorry. I was looking at memory
consumption of eds
last week. You can find results on my weblog (http://slusnys.wordpress.com/).

Federico took a look at my code, comments from him and from other
members of community
motivated me to do some polishing. I am doing this just now.

Than I have to modify ECalBackend, so that another backends can use
interval trees.

Cheers

Stanislav Slusny