Allow tool tests to assert properties about command, standard output, and standard error.
See test/functional/tools/job_properties.xml for example. Provides full access to assertion based XML tags - tabular and XML based assertions probably not so interesting so these include - has_text, has_line, not_has_text, has_text_matching, has_line_matching.
Implement expect_failure and expect_exit_code on test tag of tools.
Merged in jmchilton/galaxy-central-fork-1 (pull request #617)

Allow tool tests to assert properties about command, standard output, and standard error.