Extension points

phil/qr-code

The package is at 0.x: its extension points are stable only from its 1.0 release. Until then, a minor version may change them, and its CHANGELOG says how.

To	Do
Draw a code another way — PDF, terminal	Read `QrCode::rows()` or `isDark()`, and `zone`, and draw the modules; `SvgWriter` and `PngWriter` are two such drawings
Write another kind of content	Implement `Contract\Content`: its `payload()`, escaped as its format requires, and a `label()` without secrets
Choose the segments	Build `Segment`s and pass them to `QrCode::fromSegments()`
Keep a code the same size whatever its text	Pass `$minVersion` to `QrCode::encode()`
Keep a code the same across versions of the package	Pass `$mask` to `QrCode::encode()`
Leave room for a logo	Pass `$logoZone` to `QrCode::encode()`, and a `Logo` to the writer

The classes under Internal are not extension points.