ikaaro 0.75 released

Almost two years have passed since the previous major release of the ikaaro web framework, and the itools library. The new release has tons of changes, so many I will not try to list them here.

This release is used by BePatient and some intranets.

I have labelled this release as beta, because the code to upgrade from the previous major release (0.62) is missing. Though, this is probably unfair since this version is already being used in production, and it is recommended to use it for new projects.