Instead of using a linked list, which is incredibly fragmented, a
vector keeps all pointers together. Keeps all our stuff together and
in theory we should have less cache misses when deleting pages.
It does introduce the issue of fragmenting, where if we allocate and
then delete many times a lot of the heap vector will be empty so
traversal will be over a ton of useless stuff.
struct.c is used for the general construction, inspection and deletion
of the virtual machine structure (vm_t). runtime defines the
execution routines, error enum, lookup tables, etc.
