Restructure project directories (#333)

`/client/web` -> `/frontend`
`/client/cli` -> *delete for now*
`/client/native` -> *delete for now*
`/core/editor` -> `/editor`
`/core/document` -> `/graphene`
`/core/renderer` -> `/charcoal`
`/core/proc-macro` -> `/proc-macros` *(now plural)*

editor/src/lib.rs

@@ -0,0 +1,77 @@
+// since our policy is tabs, we want to stop clippy from warning about that
+#![allow(clippy::tabs_in_doc_comments)]
+
+extern crate graphite_proc_macros;
+
+mod communication;
+#[macro_use]
+pub mod misc;
+mod document;
+mod frontend;
+mod global;
+pub mod input;
+pub mod tool;
+
+pub mod consts;
+
+#[doc(inline)]
+pub use misc::EditorError;
+
+#[doc(inline)]
+pub use graphene::color::Color;
+
+#[doc(inline)]
+pub use graphene::LayerId;
+
+#[doc(inline)]
+pub use graphene::document::Document as SvgDocument;
+
+#[doc(inline)]
+pub use frontend::Callback;
+
+use communication::dispatcher::Dispatcher;
+// TODO: serialize with serde to save the current editor state
+pub struct Editor {
+	dispatcher: Dispatcher,
+}
+
+use message_prelude::*;
+
+impl Editor {
+	pub fn new(callback: Callback) -> Self {
+		Self {
+			dispatcher: Dispatcher::new(callback),
+		}
+	}
+
+	pub fn handle_message<T: Into<Message>>(&mut self, message: T) -> Result<(), EditorError> {
+		self.dispatcher.handle_message(message)
+	}
+}
+
+pub mod message_prelude {
+	pub use crate::communication::generate_hash;
+	pub use crate::communication::message::{AsMessage, Message, MessageDiscriminant};
+	pub use crate::communication::{ActionList, MessageHandler};
+	pub use crate::document::{DocumentMessage, DocumentMessageDiscriminant};
+	pub use crate::document::{DocumentsMessage, DocumentsMessageDiscriminant};
+	pub use crate::document::{MovementMessage, MovementMessageDiscriminant};
+	pub use crate::frontend::{FrontendMessage, FrontendMessageDiscriminant};
+	pub use crate::global::{GlobalMessage, GlobalMessageDiscriminant};
+	pub use crate::input::{InputMapperMessage, InputMapperMessageDiscriminant, InputPreprocessorMessage, InputPreprocessorMessageDiscriminant};
+	pub use crate::misc::derivable_custom_traits::{ToDiscriminant, TransitiveChild};
+	pub use crate::tool::tool_messages::*;
+	pub use crate::tool::tools::crop::{CropMessage, CropMessageDiscriminant};
+	pub use crate::tool::tools::eyedropper::{EyedropperMessage, EyedropperMessageDiscriminant};
+	pub use crate::tool::tools::fill::{FillMessage, FillMessageDiscriminant};
+	pub use crate::tool::tools::line::{LineMessage, LineMessageDiscriminant};
+	pub use crate::tool::tools::navigate::{NavigateMessage, NavigateMessageDiscriminant};
+	pub use crate::tool::tools::path::{PathMessage, PathMessageDiscriminant};
+	pub use crate::tool::tools::pen::{PenMessage, PenMessageDiscriminant};
+	pub use crate::tool::tools::rectangle::{RectangleMessage, RectangleMessageDiscriminant};
+	pub use crate::tool::tools::select::{SelectMessage, SelectMessageDiscriminant};
+	pub use crate::tool::tools::shape::{ShapeMessage, ShapeMessageDiscriminant};
+	pub use crate::LayerId;
+	pub use graphite_proc_macros::*;
+	pub use std::collections::VecDeque;
+}