Nikkei rises to fresh 6-month high; Nissan jumps on strong results

* Strong earnings offset weak U.S. housing data * Market focused on FOMC, U.S. jobs data this week By Ayai Tomisawa TOKYO, July 29 (Reuters) - Tokyo stocks rose to a fresh six-month high on Tuesday morning, as strong earnings from the likes of Nissan Motor Co suggested Corporate Japan has managed to weather a recent rise in the national sales tax. The Nikkei gained 0.5 percent to 15,612.66 in mid-morning trade, the highest level since January 23. Nissan jumped 4.5 percent a