The pain for Tesla investors is unending as a rough week nears an end. Tesla shares slipped another 4% today, dropping to multi-year lows and giving the stock a nearly 16% drop for the week, as of midday trading. Tesla investors have been blaming CEO Elon Musk for the near term weakness in the stock, with Twitter the main source of the criticisms. Long-term shareholders see him as distracted from running Tesla and abandoning the company during a critical period, and bringing downward pressure on the stock with recent share sales. Gary Black, a prominent long-term Tesla stockholder, believes today’s…