improve the list abstraction with "struct list_head" and "struct list"

both structs are actually just uint32_t's in disguise, using bitfields
to avoid the need for explicit bit operations, and using two type names
to hide the RAZOR_IMMEDIATE hack from the public API

 .gitignore

 *.o

 *~

 *.repo

 razor

 test-driver

 pkgs

 set

 primary.xml.gz

 filelists.xml.gz