HUD always enables follow mode

[mike-kaufman]

Repro:

1. launch express.test.app
2. open http://localhost:3000 in one browser window.
3. open glimpse at http://localhost:3000/glimpse/client in 2nd browser window
4. disable follow-mode in glimpse client
5. return to frist browser window
6. click hud
7. follow-mode is turned back on.

Expected:
follow-mode toggles are persisted & not changed by hud

Actual:
HUD link includes follow=true query param which turns hud back on.