dcs-hotload 2.0.0

• Breaking: user-scripts/ is now user-f10/, read only by the F10 menu: rename the folder.
  Hotload says so when it finds only the old one. F10 runs are labelled f10/<path> in dcs.log,
  so an entry never shares a label with an inbox command. Setup deploys user-f10/, and an update
  over user-scripts/ says to rename it.
• Breaking: Hotload.run is removed. Send what the entry contains, or call into user-lib/;
  a step that may fail without failing the rest is a separate mailbox command.
• A library that waits at its top level says so: load <name>: a library's top level cannot wait ... -- move it into a function, in place of Lua's "attempt to yield across
  metamethod/C-call boundary".
• Hotload.stop(label) stops one run by its label, from the mailbox or anywhere: a driver can
  end a command that waits forever without Stop all runs. hotload.sh's timeout message says
  how.