Elon Musk is cutting Tesla Inc.'s full-time workforce by 7 percent, warning in a blog post that the "road ahead is very difficult" as he tries to make electric cars more affordable for the mass market. The shares fell 7.6 percent in pre-market trading after the Palo Alto, California-based company said it managed to eke out a profit in the fourth quarter -- though a narrower one than the hard-won third-quarter profit it reported in October, the chief executive officer said [...]