Assegnate 3 su 5 stelle

In order to make it working I've done the following:

- Stop Thunderbird
- Correct extensions\en-GB@dictionaries.addons.mozilla.org\install.rdf: put version 3.0 for first two entiries.
- Remove extensions.cache and extensions.rdf from profile directory (or move them to TEMP)
- Start Thunderbird

Questa recensione riguarda una versione precedente (1.19) del componente aggiuntivo.