Update README and main plugin logic for improved menu processing

- Enhanced README.md with build, development, and testing instructions.
- Refactored main.js to separate menu block processing into a dedicated method.
- Improved error handling during plugin loading.
- Streamlined link processing for internal, external, and file links.
- Added support for multi-line dataview queries.
- Updated manifest.json version to 1.4.

manifest.json

@@ -1,7 +1,7 @@
 {
 	"id": "menu-plugin",
 	"name": "Obsidian Menus",
-	"version": "1.3",
+	"version": "1.4",
 	"minAppVersion": "0.15.0",
 	"description": "Create custom menus using code blocks with links and CSS styling.",
 	"author": "Olivier Legendre",