TestPAK: embedded tests for Octave scripts

• example, demo
  example('name') shows sample code for using function 'name', and demo('name') runs that code. The examples are stored in the script file for each function. Not all functions have examples (yet).
• test
  test('name') runs all test code associated with the function 'name'. The test code is stored in the script file for each function. Not all functions have tests written (yet).
• assert, pretty
  assert(x,y) produces an error if x != y. pretty(x) formats the data in x, no matter what it is, and is used by assert to construct the error message.
• emacs support for test code in octave scripts. Also available as a diff against 2.0.14