move contents of taskchampion repo to tc/

rust/lib/src/result.rs

@@ -0,0 +1,9 @@
+/// A result from a TC operation.  Typically if this value is TC_RESULT_ERROR,
+/// the associated object's `tc_.._error` method will return an error message.
+/// cbindgen:prefix-with-name
+/// cbindgen:rename-all=ScreamingSnakeCase
+#[repr(i32)]
+pub enum TCResult {
+    Error = -1,
+    Ok = 0,
+}