There's nothing like a double-digit dividend raise to get the bulls running.There are few things income investors like more than a meaty dividend raise. Argan (AGX 3.95%) declared one on Wednesday, and the market rewarded the construction company with a nearly 4% bump in its share price. That was significantly better than the 0.3% increase posted by the benchmark S&P 500 index.A healthy boostMost dividend raises are cautious, representing only incremental improvements over their predecessors. This sure isn' ...