Lets-plot

Added
- Support for interactive maps.
- The `as_discrete()` function.
- Polynomial regression of an arbitrary degree (the`lm` smoothing method) in *geom_smooth*.
- `axis_tooltip`, `axis_tooltip_x`, `axis_tooltip_y` parameters in `theme()`
- Kaggle and Datalore notebook demos.

Fixed
- Severe performance degradation when using discrete scales [[119](https://github.com/JetBrains/lets-plot/issues/119)].
- Opaque background to better support PyCharm dark theme [[121](https://github.com/JetBrains/lets-plot/issues/121)].
- Auto-detection of a Kaggle environment.
- Limits on the maximum plot size [[115](https://github.com/JetBrains/lets-plot/issues/115)].
- Installation instructions for Windows users [[118 MinGW](https://github.com/JetBrains/lets-plot/issues/118)].

Changed
- More slick shape for tooltips on the axis.

Added

- `facet_wrap()` function.
- in `facet_grid()` function:
- Ascending/descending ordering of faceting values.
- Formatting of faceting values.

See: [Facets demo](https://nbviewer.jupyter.org/github/JetBrains/lets-plot-kotlin/blob/master/docs/examples/jupyter-notebooks/facets.ipynb)

- The `format` parameter in positional scales: formatting tick labels on X/Y axis. Supported types are `number`
and `date/time`.

Example:

scale_x_datetime(format="%b %Y")
scale_x_continuous(format="is {.2f}")


Demo: [Formatting demo](https://nbviewer.jupyter.org/github/JetBrains/lets-plot-kotlin/blob/master/docs/examples/jupyter-notebooks/formatting_axes_etc.ipynb)

See also: [Formatting](https://github.com/JetBrains/lets-plot-kotlin/blob/master/docs/formats.md)


- The `guides()` function [[52](https://github.com/JetBrains/lets-plot/issues/52)].

- In tooltip customization API:
- option `color` overrides the default tooltip color:

geom_xxx(tooltips=layer_tooltips().color("red"))


See: [Tooltip Customization](https://github.com/JetBrains/lets-plot-kotlin/blob/master/docs/tooltips.md).

Changed

- Built with Lets-Plot v2.0.1 (was v1.5.6).
- All Java Swing demos were updated to use new `plot components` (new in Lets-Plot v2.0.1).
- The "Minimal demo" was updated:
- [`Main.kt` (Batik)](https://github.com/JetBrains/lets-plot-kotlin/tree/master/demo/jvm-batik/src/main/kotlin/minimalDemo)
- [`Main.kt` (JavaFX)](https://github.com/JetBrains/lets-plot-kotlin/tree/master/demo/jvm-javafx/src/main/kotlin/minimalDemo)

Fixed

- `show()` should actually show a plot [[51](https://github.com/JetBrains/lets-plot-kotlin/issues/51)]
- Facet grid truncated in jupyter [[28](https://github.com/JetBrains/lets-plot-kotlin/issues/28)].

The majority of fixes in the core Lets-Plot vv 2.0.0, 2.0.1 are also applicable to this release.

See the Lets-Plot [CHANGELOG.md](https://github.com/JetBrains/lets-plot/blob/master/CHANGELOG.md).

Fixed
- tooltip not showing in geom_polygon

Added

- Correlation plot builder.

Example: [correlation_plot.ipynb](https://nbviewer.jupyter.org/github/JetBrains/lets-plot-kotlin/blob/master/docs/examples/jupyter-notebooks/correlation_plot.ipynb)

- The `gggrid()` plot layout utility

Example: [correlation_plot.ipynb](https://nbviewer.jupyter.org/github/JetBrains/lets-plot-kotlin/blob/master/docs/examples/jupyter-notebooks/correlation_plot.ipynb)

- In tooltip customization API:
- options: `center` and `middle` (anchor).
- option 'minWidth'.

Example: [tooltip_config.ipynb](https://nbviewer.jupyter.org/github/JetBrains/lets-plot-kotlin/blob/master/docs/examples/jupyter-notebooks/tooltip_config.ipynb)

- The `naText` parameter in `geom_text()`

Changed

- Built with Lets-Plot v1.5.6 (was v1.5.4).

See Lets-Plot [CHANGELOG.md](https://github.com/JetBrains/lets-plot/blob/master/CHANGELOG.md) for changes and fixes in
1.5.5, 1.5.6.

Added

- GeoTools support (see [geotools.md](https://github.com/JetBrains/lets-plot-kotlin/blob/master/docs/geotools.md)).
- API for tooltip customization (
see [tooltips.md](https://github.com/JetBrains/lets-plot-kotlin/blob/master/docs/tooltips.md)).
- `geom_map()`.
- `labelFormat` parameter in `geom_text()`.
- `reverse` parameter in `scale_x/y_discrete()`.
- `scale_x_discrete_reversed()`, `scale_y_discrete_reversed()`

Changed
- Built with Lets-Plot v1.5.4 (was v1.5.2).

See Lets-Plot [CHANGELOG.md](https://github.com/JetBrains/lets-plot/blob/master/CHANGELOG.md) for changes and fixes in 1.5.3, 1.5.4.

Fixed
- `ggsave()` ignores raster format file extension.
- `as_discrete()`: if more than one is used in the same mapping block, then all but one of them are ignored.

Added

Changed

Fixed