stigmem Plugin Signature Enforcement Bypass via Configuration

stigmem-node 0.9.0a1 allows plugin signature enforcement to be disabled via a single configuration flag without a second explicit acknowledgment. If that setting is carried into an environment where plugin directories are writable by less-trusted users, unsigned (potentially malicious) plugin code could be loaded and executed, resulting in arbitrary code execution. Fixed in 0.9.0a2, which requires a second explicit acknowledgment to disable signature enforcement.