Amazon has announced a refresh of the Fire HD 8 with a vastly cheaper price and new innards, and it may be the first tablet from the retail giant that's worth picking up.The Fire HD 8 features an 8-inch display with a pixel resolution of 1280 x 800 equalling 189 pixels-per-inch. While it's all powered by a quad-core 1.3GHz processor and 1.5GB of RAM.Amazon...