Improve test suite
Improve test suite

* Use -cleanup and -setup where applicable.
* Use "-resultCodes error" to test for errors.
* Reformat results of some tests to fit into a
  terminal window.

NOTE that this change exposes errors in the
implementation of tests sign-verify-1.3
and sign-verify-1.4, and these errors are not
fixed in this commit.

kurnevsky/tclgpg,kurnevsky/tclgpg