Use type conversions from protocol crate

This also changes ToSql and FromSql to explicitly deal in byte buffers.

codegen/src/main.rs

@@ -6,12 +6,12 @@ use std::ascii::AsciiExt;
 use std::path::Path;
 
 mod sqlstate;
-mod types;
+mod type_gen;
 
 fn main() {
     let path = Path::new("../src");
     sqlstate::build(path);
-    types::build(path);
+    type_gen::build(path);
 }
 
 fn snake_to_camel(s: &str) -> String {

codegen/src/type_gen.rs

@@ -20,7 +20,7 @@ struct Type {
 }
 
 pub fn build(path: &Path) {
-    let mut file = BufWriter::new(File::create(path.join("types/types.rs")).unwrap());
+    let mut file = BufWriter::new(File::create(path.join("types/type_gen.rs")).unwrap());
 
     let ranges = parse_ranges();
     let types = parse_types(&ranges);