3.0 project bake cleanup

A few bits of cleanup related to project task.

* Remove dead code that is now uncalled.
* Search $PATH for composer when it is not in ROOT/composer.phar. A few people have asked for project bake to look in $PATH as they found it confusing that bake did not automatically find it.

I didn't write tests for the findComposer() method as I didn't feel it was worth the effort to mess around with $PATH and copying composer.phar around.