Fix mleibman#380 - asyncPostProcess is fired too often when the array…

….prototype has been extended.

Fix mleibman#380 - asyncPostProcess is fired too often when the array…

….prototype has been extended.

Fix mleibman#302 and mleibman#319 (though the user seems confused abo…

…ut his own bug report):

- Use a fixed position (i.e. always on screen) hidden DIV as a focusable keyboard event sink, and focus on that instead of the grid canvas.  Since it is always in the viewport, no scrolling occurs.  We still listen to events from editors bubbling up to the canvas and set focus on canvas clicks.
- Exposed a "focus()" method on the grid.
- Got rid of IE's .setActive() call since we have a better mechanism now.
- Fixed "fast" arrow key navigation when asyncEditorLoading is on.

Removed search filter from grouping example to simplify it a bit (plu…

…s it wasn't working).

Removed "alpha" references.

Tagging the latest stable release as we switch to 2.0 branch.

Merged in Daptiv changes.

- ADDED:  "toolTipMaxLength" option.
- FIXED:  not all rows getting removed by updateRowCount().
- ADDED:  onHeaderContextMenu event now passes in a column definition as a second parameter.
- ADDED:  "getGridPosition" method.

- ADDED: preliminary support for cell range selection ("enableCellRan…

…geSelection" option, "onCellRangeSelected" event)

Merge branch 'master' of github.com:mleibman/SlickGrid

- FIXED: perf regression with respect to scrolling responsiveness