In some cases natural use of abstraction in avo programs can lead to redundant move instructions, specifically self-moves such as MOVQ AX, AX. This does not produce incorrect code but it is incorrect and inelegant.
This diff introduces a PruneSelfMoves pass that removes such unnecessary instructions.
Closes#76
The Go assembler merges MOVD/MOVQ instruction forms. The logic in the
avo instruction loader was discarding the MOVD forms. This diff should
merge them correctly.
Updates #50
