Add template lookup to retrieve fixed-width integer types for given bit widths.

seec::GetInt<N>::type gives the intN_t type for N=8,16,32,64.
seec::GetUInt<N>::type gives the uintN_t type for N=8,16,32,64.
Update SimpleWrapper system.

Update value notification to convert integer types to the appropriate
fixed-width type for their size, to avoid ambiguity when calling
TraceThreadListener::notifyValue().

Add a "IgnoreNull" flag to WrappedOutputPointer. If this flag is true, then no
error checking or recording will be performed for NULL values.

Check if the value of errno changes when the original function is called and,
if it does, update the state of errno.