Use %S for regular string in pkg_snprintf
Use pkg_snprintf to create the url string
Fix build
Add a new pkg_vcmp function to compare versions of 2 struct pkg *
When upgrading a pkg, test for the direction the version number is
changing in.
Revert "Add a new pkg_vcmp function to compare versions of 2 struct pkg *"

This function had no real usage yet
This reverts commit e232d6021772f94bcd19a72faad50a23bfbedc00.
Use new pkg_version_change() function