Removed macro facets

Macros, placeholders, etc. will all be handled by std eventually so they shouldn't appear in the protocol or the host

orchid-host/src/lib.rs

@@ -5,5 +5,5 @@ pub mod expr;
 pub mod extension;
 pub mod lex;
 pub mod parse;
-pub mod tree;
 pub mod subprocess;
+pub mod tree;