clean up TODO comments

Use the convention // TODO({author})
app: Provide custom copyRecursive implementation

Override `Workspace.copyRecursive` with yeoman's `directory` to enable
conflict detection for templated files.
test/app: check *.js files are created
actions: validate the workspace dir in loadProject

Call `Workspace.isValidDir` from `actions.loadProject` to ensure the
working directory is a valid workspace.