Releasing v2.2

- Improved :Tableize to accept a {patter} in a similar way as
  :Tabularize does. eg.)
      :Tableize/;
  The above command will tableize the selection taking ';' as the
  delimiter rather than the default ',' defined by the
  g:table_mode_delimiter option. If you do not provide a pattern, the
  default delimiter will be used.
- Updated doc/table-mode.txt
- Updated README.md
- Added tags to .gitignore to avoid checking in tags file.