Isqlite

- The isqlite library is now deprecated. This will be the last release.

Fixed
- `isqlite delete` now prints a nice error message instead of a stack trace when the row to be deleted does not exist.

Added
- The `Database` and `AutoTable` constructors now accept a `use_epoch_timestamps` parameter to store auto timestamps as seconds since the Unix epoch instead of ISO 8601 datetime strings. (69)
- A `Database.delete_many_by_pks` method to delete multiple rows simultaneously using a list of PKs. (77)

Changed
- `isqlite update` now treats `NULL` as a special value, in line with `isqlite iupdate`.
- `isqlite delete` now displays the string values of foreign keys when printing a row prior to deletion.

Fixed
- In `isqlite icreate`, empty values are ignored instead of being inserted as NULLs or empty strings. This is useful when the column definition specifies a default value.
- `isqlite update` now reports an error when the row with the given primary key is not found.
- `Database.select` now accepts a tuple for the `order_by` parameter to sort by multiple columns. (71)

Added
- `isqlite icreate` and `isqlite iupdate` commands to interactively create and update rows.
- A `detect_renaming` parameter has been added to `Database.diff` and `Database.migrate`, and a `--no-rename` flag has been added to `isqlite diff` and `isqlite migrate`, allowing isqlite's renaming detection to be disabled in case it gives erroneous results.
- The return value of `Database.get_or_insert` now has an `inserted` attribute to indicate whether or not a new row was inserted into the database. (60)

Changed
- `isqlite sql` no longer prints anything if the SQL query returned no rows. (66)

Fixed
- Previously, under some circumstances `Database.diff` would identify a column as renamed (e.g., `a --> b`) even though the old column (`a`) was still in the table. This has been fixed. (67)
- `isqlite update` with `--auto-timestamp` turned on (the default) no longer updates the `created_at` timestamp field. (68)
- `isqlite create` and `isqlite update` no longer crash when a value in a command-line argument contains an equals sign.
- `isqlite get` now prints a helpful error message instead of crashing when the row does not exist.
- `isqlite schema <table>` now prints a helpful error message when the table does not exist.

Added
- `Database.select`, `Database.get`, and related methods now accept a `columns` parameter to specify the set of columns to be returned for each row. (63)
- The `Database` constructor now accepts a parameter `enforce_foreign_keys` which can be set to false to turn off foreign-key constraint enforcement.
- All `columns` constructors except `boolean` and `primary_key` now accept a `unique` parameter to enforce a SQL `UNIQUE` constraint. (64)
- `isqlite create` as an alias for `isqlite insert` and `isqlite list` as an alias for `isqlite select`. (61)

Changed
- `Database.update` now returns the count of rows updated, and `Database.update_by_pk` returns a boolean indicating whether or not the row was updated.

Fixed
- Thanks to upstream fixes in the sqliteparser library, isqlite can now handle some SQL syntax it would previously choke on, including `VARCHAR(...)` column types, multi-word column types, and `NULL` column constraints.
- The `isqlite migrate` and `isqlite diff` commands now give better error messages for invalid schema files.
- The `isqlite sql` command now gives a more informative error message when attempting to modify the database without the `--write` flag. (62)

Fixed
- The PyPI package now depends on the correct version of `sqliteparser`.