Avoid requiring asdf-driver on asdf3.
Remove a function redefinition from asdf/filesystem.
Update TODO items.
Update xcvb to require asdf 3.0.1.6.
Fix xcvb::main to set the syntax, and most importantly, package.
Fix more things broken by the refactoring of xcvb-driver into uiop.
Fix the interface between xcvb and its the driver.
Update entry-point in build.xcvb to reflect new calling convention.
Hush some SBCL compiler notes on driver.lisp