multiSelect should be hidden on GridView

[yAdEs]

I can't use multiselect in gridpanel in designer after it update to #311, I set the multiselect = true in gridview, but it also doesn't work.

[aconran]

multiSelect should be hidden in the GridView. I have filed a bug.

The proper way to do this is to add a selection model to your Grid Panel and set the selection models mode to 'MULTI'.