add basic test environment

DEPENDS_ON: deb:shelltestrunner
fix test for help subcommand
add usage tests for subcommands
fix usage for reject subcommand
restructure test directory
use bin/run-test for running all the tests
add tests for basic 'list' and 'rm'
add test for ticket creation
fixup! add test for ticket creation
Merge branch 'olf/add-tests' into develop