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)*

frontend/wasm/tests/web.rs

@@ -0,0 +1,10 @@
+#![cfg(target_arch = "wasm32")]
+
+use wasm_bindgen_test::*;
+
+wasm_bindgen_test_configure!(run_in_browser);
+
+#[wasm_bindgen_test]
+fn pass() {
+	assert_eq!(1 + 1, 2);
+}