discontinuing Flattr for lxml

I removed lxml from Flattr. The outcome is just way below ground. The Flattr revenue for the project over the last years was a pretty constant 6 EUR per month. Minus taxes. And Flattr already kept their 10% share, which is what bugs me most, I guess. That leaves Paypal as the current (and certainly better) alternative if you want to support the development behind lxml.