duplicate cell IDs in summary, editChange handles incorrect row for editable checkbox cells

Only the last commit is relevant:

https://github.com/wolfmanx/w2ui/commit/851244ab4f58b18aafa3412fbc4841629b57d652

Three issues:

1. The row number/select/expand cell IDs for summary records are duplicated.
2. A cell which is editable as type checkbox is also shown in summary record (which is fine with me!), however method editChange cannot distinguish between normal records and summary records and will therefore change the wrong checkbox.
3. selecting something in the summary record (mouseMove) causes an exception

I have made examples for 2 (just click on the checkbox in the summary line and watch record no. 1):

- w2ui current master: http://jsfiddle.net/hWZzG/4/
- w2ui with changes: http://jsfiddle.net/AGF75/4/

The demo shows, what I'm aiming at: add a summary row to enter/display detailed search expressions