Fixes #22 : Integrate composer into project. Composer now loads required
development dependencies (e.g. phpunit, phpdocumentor) and generates autoload
file. autoload file is now pulled in by phing (to find phpunit) and by
bootstrap.php (to find classes-under-test). Got rid of phpunitphar
configuration variable. Got rid of manually-generated autoload.php.
Tests run both from phing via command-line and from NetBeans IDE, even when
phpunit is uninstalled globally. Phpunit will _NOT_ run manually from
command-line without adding vendor/bin to your path.
May need additional testing to verify that correct versions of all dependencies
are being loaded by phing and not from PEAR or global installation.
May be worth a sourceable shell script to add the vendor bin to project path.

Question for naval-contemplation: how do we track required version of phing
itself and/or composer?