Dash-table

- visually freezing rows and/or columns
- filtering in either FE or BE, basic filtering UI
- sorting in either FE or BE, basic sorting UI
- pagination in either FE or BE, basic pagination UI
- performance optimizations
- basic coverage through e2e, integration and unit tests

Virtualization
- See v_be_page_usage.py and v_fe_page_usage.py for FE and BE usage scenarios.
- virtual_dataframe and virtual_dataframe_indices are exposed and expected to be *readonly*. Setting them from the BE will have no impact on the FE display.
FE Virtualization
- BE is not expected to update the dataframe when the virtualization settings are updated.

BE Virtualization
- BE is expected to update the dataframe when the virtualization settings are updated.

Freeze Top Rows (Limitations)
- the table styling is forced to { table-layout: fixed; width: 0 !important; } to ensure the frozen section and the rest of the table stay in sync (width-wise); this means that the width of the table is only driven by the width of the columns (default width is 200px)
- can't freeze rows and columns at the same time

Freeze Left Columns (Limitations)
- performance is highly impacted if the table is in a scrollable container as the frozen columns position has to be recalculated on each scroll event; impact is minimal up to 50-100 items and makes the table difficult to use with 250-500 items
- can't freeze rows and columns at the same time
- when using merged headers, make sure that the number of fixed columns respects the merged headers, otherwise there will be some unresolved visual bugs/artifacts
- rows are assumed to all have the same height

Deletable Columns (Limitations)
- there might be unintended side-effects if used with BE virtualization (the act of deleting a column / columns modifies the dataframe)

Performance Improvements
- Table now renders and navigates faster
- Typing in cell does not modify dataframe until focus is lost / edit is confirmed ("enter" or "tab)

Deprecated
- prop "update_on_unfocus" has been removed

Fixed
- Fix regression for user select
Sorting arrow will no longer highlight.

Changed
- Improve performance when the user clicks outside of the table [104](https://github.com/plotly/dash-table/pull/104)
Clicking outside of the table was setting the table's `is_focused` property.
Setting component properties in Dash can be expensive: it can cause the
entire app to re-render.
Now, clicking outside the table will update the component more efficiently,
prevent excessive application re-renders.

Fixed
- Fix incorrect border around table cells when not filled [102](https://github.com/plotly/dash-table/pull/102) [#101](https://github.com/plotly/dash-table/issues/101)
Table styling has been changed for frozen rows and columns. Default styling change from:

- frozen rows: { height: 500px } to { height: fit-content, max-height: 500px }
- frozen columns: { width: 500px } to { width: fit-content, max-width: 500px }

Fixed
- Fix dropdown position & behavior on scroll [96](https://github.com/plotly/dash-table/issues/96)
Limitation: The dropdown in fixed columns behaves differently from the dropdown in the non-fixed portion of the table. Because of layers of overflow & positioning, the dropdown does not show outside of the table is instead part of it. Opening the dropdown in bottom rows will require scrolling vs. displaying on top of the table.

Added
Basic Filtering & Preparation work for advaced filtering
- Additional filtering_type prop that can take value 'basic' (or eventually 'advanced')
This prop defines whether the user is presented with the UI to filter by column or with complex expressions
The default value is 'basic'

Note: The filtering row counts against n_fixed_rows

- Additional filtering_types prop that takes an array of values with valid values 'basic' (and eventually 'advanced')
This prop defines what type of filtering are available to the user
The default value is ['basic']

Note: This value needs to be consistent with `filtering_type`