Develop unit/self test framework using ippeveprinter

[michaelrsweet]

Currently there is no automated way of testing the self-certification tools. Goals:

• Use ippeveprinter to simulate a variety of printers, both conforming and non-conforming.
• Develop self-test scripts for Windows and macOS/Linux (that can be bundled with the tools) that runs them against ippeveprinter.
• Make this self-test script part of the release process, such that a clean install should be able to pass the self-test on any of our supported platforms.

[michaelrsweet]

[master a366dd4] Add "make test" target and "buildtest.sh" script (Issue #56, Issue #62)