Interface Exposure

Exposed functions needed to attach an AXE simulation to the `xgdb` debugger. 

Debug `printf`s have been removed, and test summary is:

```
Testing Time: 18.59s
********************
Failing Tests (1):
    axe :: SystemCalls/overlays.xc

  Expected Passes    : 74
  Unexpected Failures: 1
```
This should return an int instead of a bool since the header should be includable from C.