Add a lot of new stuff to the compile mod

* compile::sym is now compile::name
* add basic block structure
* add visitor pattern
* some other minor things (e.g. syn::ast::prelude)

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/compile/block.rs

@@ -0,0 +1,6 @@
+use crate::compile::ir::Body;
+
+// basic block
+pub enum Block {
+    Body(Body),
+}