Minor: name_primitive => __kernel_primitive in a comment


git-svn-id: http://www.latex-project.org/svnroot/experimental/trunk@4652 de43f980-851b-0410-b2f7-c40aca1f87e0
Update \in_to_[base]:n functions

This check-in:
 1) Alters the behaviour of \int_to_base:nn
 2) Shortens the 'shortcut' versions to use bin/hex/bin
 3) Introduces separate 'lower' and 'upper' case versions of
    \int_to_base:nn and \int_to_hex:n



git-svn-id: http://www.latex-project.org/svnroot/experimental/trunk@4653 de43f980-851b-0410-b2f7-c40aca1f87e0