Translations::add_entry_or_merge( array|Translation_Entry $entry )

	function add_entry_or_merge($entry) {
		if (is_array($entry)) {
			$entry = new Translation_Entry($entry);
		}
		$key = $entry->key();
		if (false === $key) return false;
		if (isset($this->entries[$key]))
			$this->entries[$key]->merge_with($entry);
		else
			$this->entries[$key] = &$entry;
		return true;
	}