And change verbiage to not refer to "Emergency Stop."

Arduino doesn't (always) support `float` formatting in strings. So either cast to `int` or use `dtostrf()` to fix these usages.

- Use the return value from probe_pt during `G34`
  Eliminate the assumption that probe_pt leaves current_position set to values relative to the probed points. This is not always true, depending on the raise_after argument.
- Add '`E`' argument to `G34` command allowing stowing between each probe.