Refactor ProfileInstaller. Clean up proof-of-concept code.

 Trim this down:
	modified:   ProfileInstaller.php

 Data transfer object:
	new file:   Profile.php

 Logic for looking up info about install profiles and building out Profile
 object:
	new file:   ProfileUtility.php

 Invokes hooks in included profiles as appropriate during installation:
	new file:   InstallUtility.php

 Basic updates:
	modified:   examples/standard3/standard3.info
	modified:   profile_installer.inc
Removes unused function.