Now supports running under a sub path

Just set the SPOOLMAN_BASE_PATH environment variable and it should work.

Resolves #95

client/src/components/liveProvider.ts

@@ -1,4 +1,5 @@
 import { BaseKey, LiveEvent, LiveProvider } from "@refinedev/core";
+import { getBasePath } from "../utils/url";
 
 /**
  * A spoolman websocket event.