Removes unused command; Updates cut help (#10)

1. `max-delay` was never really implemented - quantize does the job; and
2. `cut` help was misleading - it showed `--from` and `--to` as flags in
the examples while in reality they are `start` and `end`.

Author: Ciro S. Costa

commands/cut.go

@@ -24,13 +24,13 @@ EXAMPLES:
 
      cat 1234.cast | \
        asciinema-edit cut \
-         --from=12.2 --to=15.3
+         --start=12.2 --end=15.3
 
    Remove the exact frame at timestamp 12.2 from the cast file named
    1234.cast.
 
      asciinema-edit cut \
-       --from=12.2 --to=12.2 \
+       --start=12.2 --end=12.2 \
        1234.cast`,
 	ArgsUsage: "[filename]",
 	Action:    cutAction,