C++ std::vector<T> and Rust std::vec::Vec<T> support

Add basic std::vector and std::vec::Vec support across FFI boundary.
diff --git a/tests/ffi/tests.h b/tests/ffi/tests.h
index ed6d541..9e75c37 100644
--- a/tests/ffi/tests.h
+++ b/tests/ffi/tests.h
@@ -29,6 +29,9 @@
 rust::Slice<uint8_t> c_return_sliceu8(const Shared &shared);
 rust::String c_return_rust_string();
 std::unique_ptr<std::string> c_return_unique_ptr_string();
+std::unique_ptr<std::vector<uint8_t>> c_return_unique_ptr_vector_u8();
+std::unique_ptr<std::vector<double>> c_return_unique_ptr_vector_f64();
+std::unique_ptr<std::vector<Shared>> c_return_unique_ptr_vector_shared();
 
 void c_take_primitive(size_t n);
 void c_take_shared(Shared shared);
@@ -40,11 +43,19 @@
 void c_take_sliceu8(rust::Slice<uint8_t> s);
 void c_take_rust_string(rust::String s);
 void c_take_unique_ptr_string(std::unique_ptr<std::string> s);
+void c_take_unique_ptr_vector_u8(std::unique_ptr<std::vector<uint8_t>> v);
+void c_take_unique_ptr_vector_f64(std::unique_ptr<std::vector<double>> v);
+void c_take_unique_ptr_vector_shared(std::unique_ptr<std::vector<Shared>> v);
+
+void c_take_vec_u8(const ::rust::Vec<uint8_t>& v);
+void c_take_vec_shared(const ::rust::Vec<Shared>& v);
 void c_take_callback(rust::Fn<size_t(rust::String)> callback);
 
 void c_try_return_void();
 size_t c_try_return_primitive();
 size_t c_fail_return_primitive();
+std::unique_ptr<std::string> c_try_return_string();
+std::unique_ptr<std::string> c_fail_return_string();
 rust::Box<R> c_try_return_box();
 const rust::String &c_try_return_ref(const rust::String &);
 rust::Str c_try_return_str(rust::Str);