New upload limit (Request Entity Too Large error)

Hi all,

We've set up a limit to POST requests size a few days ago as it was 
unbounded until now, and abused.

Clearly 20M was too agressive so we've increase the limit to 50M. If you 
need a higher limit a local install of the validators is the way to go.

Here's the install documentation for the markup-validator and 
validator.nu (HTML5 support):
http://validator.w3.org/docs/install.html
http://about.validator.nu/#src

Thomas