Periodically check and update ProcessInfo::_name
Currently, there is an issue where 'exec [program]' results in tab titles not being updated and not showing the process name as [program]. This is probably due to how 'exec' does not result in any change in pid and simply replaces the current process image with a different one.
Due to a lack of pid changes, Session::updateSessionProcessInfo will not call ProcessInfo::newInstance, thus not updating the ProcessInfo::_name.
This new change periodically checks and updates the _name of ProcessInfo through ProcessInfo::readProcessName, which is called by ProcessInfo::update.