Merge pull request #3 from mattcooksey1/master

FetchStage
finished decode stage, added jump to buffers, finished buffers
finshed memory and write back stages, changed buffers to singleton to allow forwarding later
Update Alu.java
Update ExecutionStage.java
Merge pull request #5 from wilson11011/patch-3

Update ExecutionStage.java
Merge pull request #4 from wilson11011/patch-2

Update Alu.java
added alu control, completed execution stage, fixed some bugs
fixed bug where alu used first operand twice instead of using second operand for register operations
fixed bug in function code mask
changed cpu execution procedure, removed threading, added some hazard dectection and forwarding
Current version
Working Version
fixed bugs in instructions.code and hardcode sll to always shift 4 because there are not enough registers to hold the shift value
fixed shift instructions and bunch of stuff
Alu component: added ALU_MUL and ALU_DIV instructions