Updated to v1.4.0

- Added `invisible` option and `showColumn` / `hideColumn` /
`isColumnInvisible` methods for changing / checking visibility of
columns.
- Added `resizable` option that allow column resizable.
- Added `getColumn` method to get columns array used for grid
initialization.
- [Important] You are allowed to call `appendGrid` methods by passing
ONE element in jQuery object only. It will not be affected if you are
already using ID, such as $("tblAppendGrid"), as jQuery selector.