Sleeping on exceptions even when numRetries is at configured limit

[vclayton]

When making a request to a node that is not available the ApiCall::makeRequest function will call sleep() regardless of the num_retries config setting, resulting in an unnecessary delay when the current $numRetries is at the configured max.

Side note, it would also be awesome for that to be a usleep() call instead to allow float values for situations where we want to do quicker error handling.