awgtpman: shore up synchronization with IOP
Several steps were taken to shore up synchronization of awgtpman to the IOP. These steps do not directly address the crash in issue in #377, but by blocking execution until the model is fully running, they may prevent the crash from ever happening.
- Ignore negative card counts from the IOP. This obviously indicates the IOP isn't loaded.
- Block execution of a seemingly loaded IOP until cycle counter is seen to change. The cycle counter doesn't start updating until the IOP is fully loaded.
- Allow up to a minute for an IOP to fully load, then exit nicely.