small fix
modified in order to suspend the cleaning mechanism of messages tables.
improved negotiateLoginPageLanguage

language matching regExp is compliant to HTTP/1.1 and language ranges
are properly served.
E.g. If users select "en-gb", they will be served any kind of English
document if British English is not available.
alter table to manage language ranges (e.g.: en-gb)
bugfix in createAvailableLayoutsList mehtod

added condition preventing an infinite while loop on non-existent layout dir
Merge branch 'master'