GUI: fixed cell content rendering

- Break words in table cells if CustomTextCell is used. It's used
  on audit log messages table. Cell content, when copied, is unchanged !

- Use sb.appendHtmlConstant() in Custom(Clickable)TextCell render() method
  instead of sb.appendEscapedLines() since passed value is already SafeHtml
  and there is no need to double escape HTML content.
- Use replace "\n" -> "</br>" to correctly display console output.
Merge pull request #375 from zlamalp/cells

GUI: fixed cell content rendering
GUI: allow numbers in attr def name
Merge pull request #376 from zlamalp/attr

GUI: allow numbers in attr def name