issue 7194: added Option "extensions.firebug.tabSize" for setting the default size of tabs
issue7194: indentUnit should be same as tabSize
Merge remote-tracking branch 'origin/master' into issue7194
issue7194: use tabs if preference replacetabs is zero
- improved coding style
Merge pull request #132 from kaljak/issue7194

Issue7194: - Add a preference for the indentation in the Command Editor