Switch to ctest crate

Extracted tests!
diff --git a/appveyor.yml b/appveyor.yml
index 7c01515..cdd5bf1 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -25,4 +25,4 @@
 
 test_script:
   - cargo test
-  - cargo test --manifest-path libc-test/Cargo.toml
+  - cargo run --manifest-path libc-test/Cargo.toml