Reexport all of the AOS essentials in a single `aos` crate

This improves the usability of aos for Rust as it allows for
clearly delineated modules and a better IDE workflow since
pulling one dependency will bring all the utilities one generally
needs.

Change-Id: I5d39d9510cee4b3867077ce46a4a45041192f3ee
Signed-off-by: James Kuszmaul <james.kuszmaul@bluerivertech.com>
diff --git a/aos/testing/aos.rs b/aos/testing/aos.rs
new file mode 100644
index 0000000..6c7795d
--- /dev/null
+++ b/aos/testing/aos.rs
@@ -0,0 +1,7 @@
+// Reexport all of the [`aos`] crate
+pub use aos::*;
+
+/// Utilities for testing an AOS application.
+pub mod testing {
+    pub use aos_test_init as init;
+}