trim: Add a more condensed usage message for error cases.
trim: Add a more condensed usage message for error cases.

When explicitly asking for help, ("apitrace help trim" or "apitrace
trim --help"), the complete help message is still provided.

But when an error case triggers a usage message, (such as an invalid
command-line argument), a more compact usage message is provided so as
to not overwhelm the error message (such as "invalid argument:
--foo").

surround-io/apitrace,joshua5201/apitrace,tuanthng/apitrace,trtt/apitrace,EoD/apitrace,PeterLValve/apitrace,trtt/apitrace,joshua5201/apitrace,surround-io/apitrace,swq0553/apitrace,schulmar/apitrace,schulmar/apitrace,surround-io/apitrace,trtt/apitrace,EoD/apitrace,schulmar/apitrace,trtt/apitrace,tuanthng/apitrace,surround-io/apitrace,PeterLValve/apitrace,EoD/apitrace,PeterLValve/apitrace,EoD/apitrace,joshua5201/apitrace,swq0553/apitrace,joshua5201/apitrace,apitrace/apitrace,joshua5201/apitrace,tuanthng/apitrace,swq0553/apitrace,tuanthng/apitrace,apitrace/apitrace,swq0553/apitrace,trtt/apitrace,tuanthng/apitrace,surround-io/apitrace,EoD/apitrace,swq0553/apitrace,apitrace/apitrace,PeterLValve/apitrace,schulmar/apitrace,apitrace/apitrace,schulmar/apitrace