allow starting commands in new tabs via CLI (fixes #304)

app/lib/lru.js

@@ -0,0 +1,15 @@
+let lru = require('lru-cache')({ max: 256, maxAge: 250 })
+
+let fs = require('fs')
+let origLstat = fs.realpathSync.bind(fs)
+
+// NB: The biggest offender of thrashing realpathSync is the node module system
+// itself, which we can't get into via any sane means.
+require('fs').realpathSync = function (p) {
+  let r = lru.get(p)
+  if (r) return r
+
+  r = origLstat(p)
+  lru.set(p, r)
+  return r
+}