Rename the legacy Graphene crate to document-legacy (#899)

* Rename /graphene to /document-legacy

* Update names in code

document-legacy/src/lib.rs

@@ -0,0 +1,22 @@
+// `macro_use` puts the log macros (`error!`, `warn!`, `debug!`, `info!` and `trace!`) in scope for the crate
+#[macro_use]
+extern crate log;
+
+pub mod boolean_ops;
+/// Contains the [Color](color::Color) type.
+pub mod color;
+/// Contains constant values used by this crate.
+pub mod consts;
+pub mod document;
+/// Defines errors that can occur when using this crate.
+pub mod error;
+/// Utilities for computing intersections.
+pub mod intersection;
+pub mod layers;
+pub mod operation;
+pub mod response;
+
+pub use document::LayerId;
+pub use error::DocumentError;
+pub use operation::Operation;
+pub use response::DocumentResponse;