Victory at migrating then compiling exscribe!

* Support user specification of dependencies for the initial build image.
* Add :load-source dependencies.
* Traverse in the correct order (reverse from what push creates)
* need to install initial Lisp files somewhere.
* correcly get asdf system dependencies from original systems
* update exscribe examples
* fix driver some more
* fix lack of backquote in define-lisp-implementation (duh),
 also fix use of sbcl's quit.
* remove some more remnants of the escaped output-path
* When we say we use cfasls, mean it.
* Find staged executables in current directory
* Rename default output from Makefile.xcvb to xcvb.mk