Added new method- `measureAllCells`- to `Grid`, `FlexTable`, and `Vir…

…tualScroll` to force-measure all cells.

This supports special use-cases where deferred measuring is not desired.

Added `estimatedRowSize` property to `FlexTable` and `VirtualScroll` to be passed through to the inner `Grid`.

Also added guard to ensure the `onScroll` callback for `Collection`, `Grid`, `FlexTable`, and `VirtualScroll` is never called with a negative number.

The inner javascript-detect-element-resize library used by `AutoSizer…

…` now passes the proper `useCapture` value when removing listeners as well. This should prevent lingering event listeners in certain cases.

Added "_center_" option for `scrollToAlignment` property of `Collecti…

…on`, `Grid`, `FlexTable`, and `VirtualScroll`.

Thanks to @edulan for the contribution!

Also added a check to avoid rendering content frmo `noContentRenderer` if `width` or `height` are 0.

Resolved edge-case bug that caused the bottom/right cells in a `Grid`…

… or `Collection` to be partially overlapped by a scrollbar.

Added `scrollToAlignment` property to `Collection`, `Grid`, `FlexTabl…

…e`, and `VirtualScroll` to offer finer-grained control of how scrolled-to cells are aligned.

Default behavior ("_auto_") remains unchanged- the least amount of scrolling will occur to ensure that the specified cell is visible.

Fixed edge-case bug where `InfiniteLoader` did not respect `minBatchS…

…ize` setting when a user was scrolling up.

Added `scrollLeft` and `scrollTop` parameters to `cellRangeRenderer` …

…callback for `Grid`.

Added `box-sizing: border-box` rules to `.FlexTable__headerRow` and `…

….FlexTable__Grid` classes to fix edge-case scrollbar bug experienced by some users.

Added `recomputeCellSizesAndPositions` method to `Collection` (to pas…

…s through to inner `CollectionView`).

Replaced single occurence of `Number.isNaN` with `isNaN` to avoid IE …

…compatibility issues.