Layout system implementation and applied to tool options bar (#499)

* initial layout system with tool options

* cargo fmt

* cargo fmt again

* document bar defined on the backend

* cargo fmt

* removed RC<RefCell>

* cargo fmt

* - fix increment behavior
- removed hashmap from layout message handler
- removed no op message from layoutMessage

* cargo fmt

* only send documentBar when zoom or rotation is updated

* ctrl-0 changes zoom properly

* Code review changes

Co-authored-by: Keavon Chambers <keavon@keavon.com>

editor/src/communication/dispatcher.rs

@@ -1,6 +1,7 @@
 use crate::document::PortfolioMessageHandler;
 use crate::global::GlobalMessageHandler;
 use crate::input::{InputMapperMessageHandler, InputPreprocessorMessageHandler};
+use crate::layout::layout_message_handler::LayoutMessageHandler;
 use crate::message_prelude::*;
 use crate::viewport_tools::tool_message_handler::ToolMessageHandler;
 
@@ -19,6 +20,7 @@ struct DispatcherMessageHandlers {
 	global_message_handler: GlobalMessageHandler,
 	input_mapper_message_handler: InputMapperMessageHandler,
 	input_preprocessor_message_handler: InputPreprocessorMessageHandler,
+	layout_message_handler: LayoutMessageHandler,
 	portfolio_message_handler: PortfolioMessageHandler,
 	tool_message_handler: ToolMessageHandler,
 }
@@ -76,6 +78,7 @@ impl Dispatcher {
 				InputPreprocessor(message) => {
 					self.message_handlers.input_preprocessor_message_handler.process_action(message, (), &mut self.message_queue);
 				}
+				Layout(message) => self.message_handlers.layout_message_handler.process_action(message, (), &mut self.message_queue),
 				Portfolio(message) => {
 					self.message_handlers
 						.portfolio_message_handler

editor/src/communication/message.rs

@@ -31,6 +31,8 @@ pub enum Message {
 	#[child]
 	InputPreprocessor(InputPreprocessorMessage),
 	#[child]
+	Layout(LayoutMessage),
+	#[child]
 	Portfolio(PortfolioMessage),
 	#[child]
 	Tool(ToolMessage),