Closes #112.

### Summary of Changes

Rename `fit_transform` to `fit_and_transform` to better indicate that
this method combines the two steps `fit` and `transform`.

---------

Co-authored-by: nikhilraj2003 <Nikhilraj@720>
Co-authored-by: Lars Reimann <mail@larsreimann.com>
Co-authored-by: dev-DTECH <deep64222@gmail.com>

### Summary of Changes

Rename the `drop_XY` methods of `Table` to `remove_XY`. When users want
to get rid of columns, they will probably look for "remove",
particularly, since the names of methods to include new columns and rows
start with "add".

---------

Co-authored-by: lars-reimann <lars-reimann@users.noreply.github.com>

### Summary of Changes

To be consistent with the other methods of `Table`, I've rename
`shuffle` to `shuffle_rows`. This makes it obvious that the columns are
not changed.

### Summary of Changes

To be consistent with the other methods of `Table`, I've rename `slice`
to `slice_rows`. This makes it obvious that the columns are not changed.

### Summary of Changes

We no longer raise an exception when a user creates an empty `Table`
without specifying a schema. `Table([])` is now allows.

`add_row` and `add_rows` must still be adjusted (#127) to allow adding
rows to such an empty `Table`.

---------

Co-authored-by: lars-reimann <lars-reimann@users.noreply.github.com>

Closes #116.
Closes #117.

### Summary of Changes

* Reduce code duplication
* Test that `fit` doesn't change the input table
* Test that `predict` doesn't change the input table

---------

Co-authored-by: lars-reimann <lars-reimann@users.noreply.github.com>

### Summary of Changes

Add a new method `is_fitted` to `Classifier`s and `Regressor`s to easily
check whether they have been fitted already.

---------

Co-authored-by: lars-reimann <lars-reimann@users.noreply.github.com>

…#131)

### Summary of Changes

Add a new method `is_fitted` to `TableTransformer`s to easily check
whether they have been fitted already.

---------

Co-authored-by: lars-reimann <lars-reimann@users.noreply.github.com>

Closes #113.

### Summary of Changes

* Rename subclasses:
  | old| new |
  |--------|--------|
  | IntColumnType | Integer |
  | BooleanColumnType | Boolean |
  | FloatColumnType | RealNumber |
  | StringColumnType | String |
* Add new subclass `Anything` for columns that contain any values
* Add parameter `is_nullable` to all types to indicate that null values
are allowed
* Add tests

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

### Summary of Changes

Rename `TableSchema` to `Schema` since a `Row` also has a schema.

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Closes #15.

### Summary of Changes

The `schema` parameter of the `Row` initializer is now optional. If it's
not passed explicitly, it gets inferred from the data. The column names
are set to `column_0`, `column_1`, etc.

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

## [0.8.0](v0.7.0...v0.8.0) (2023-03-31)

### Features

* create empty `Table` without schema ([#128](#128)) ([ddd3f59](ddd3f59)), closes [#127](#127)
* improve `ColumnType`s ([#132](#132)) ([1786a87](1786a87)), closes [#113](#113)
* infer schema of row if not passed explicitly ([#134](#134)) ([c5869bb](c5869bb)), closes [#15](#15)
* new method `is_fitted` to check whether a model is fitted ([#130](#130)) ([8e1c3ea](8e1c3ea))
* new method `is_fitted` to check whether a transformer is fitted ([#131](#131)) ([e20954f](e20954f))
* rename `drop_XY` methods of `Table` to `remove_XY` ([#122](#122)) ([98d76a4](98d76a4))
* rename `fit_transform` to `fit_and_transform` ([#119](#119)) ([76a7112](76a7112)), closes [#112](#112)
* rename `shuffle` to `shuffle_rows` ([#125](#125)) ([ea21928](ea21928))
* rename `slice` to `slice_rows` ([#126](#126)) ([20d21c2](20d21c2))
* rename `TableSchema` to `Schema` ([#133](#133)) ([1419d25](1419d25))