Log Message:
Updated pkg_regress to 0.3.

Changes since 0.2:

* provide usage message when called with invalid options
* moved do_test_default() from public API section in the source
* renamed private variables to not be in uppercase
* indented consistently
* replaced unnecessary ${VAR} with simple $VAR
* moved actual test execution into its own function
* when invoked with the -v option, announce which test will be run