Hack the MagickWand bindings

Using rust-bindgen to generate the bindings for the MagickWand library is
extremely difficult with the new versions of rust-bindgen. The old versions
of the generated bindings will be used for now, and nothing will be
generated at build time.

cargo test passes

Cargo.toml

@@ -12,3 +12,6 @@ build = "build.rs"
 
 [dependencies]
 libc = ">=0.2"
+
+# [build-dependencies]
+# bindgen = "0.22.1"