* Renamed set_crate_path to get_crate_path
* If the path isn't specified in the call then use the current_dir and walk up the path try to find the manifest file.
* Specify the cwd for the build test so it doesn't walk up the path. The test needs to specify the path to build, otherwise because fixtures are run in a subdirectory of the source tree it will find the Cargo.toml from the wasm-pack source repository.