Kinder Morgan has a lot of growth coming down the pipeline.Shares of Kinder Morgan (KMI +1.67%) have slumped. The natural gas pipeline stock is down about 5% year-to-date and over 15% below its 52-week high. That comes at a time when the S&P 500 is seemingly hitting a new all-time high nearly every day, as it has risen more than 15% year-to-date. While Kinder Morgan is down, the pipeline stock isn't out. Here's why the slump looks like an attractive buying opportunity for long-term investors. Cashing in on ...