combine redundant decode and decode_impl

This was bothering me all day.
start putting together actual test strategy

This change incorporates Cole's initial unit test and attempts to
establish a testing pattern for the project.
Remove accidentally added binary
Get the CartHeader creation into the Cart creation
Merge branch 'master' into cpu
attempting to wrangle memory reading
get mem to the cpu

I think I finally figured out for now how to get the Mem component into
instruction run so that they can read memory
More memory stuff
remove types.rs