Apple increased its share of the worldwide tablet market in the first quarter of 2012, according to the latest data from IDC. Apple shipped 11.8 million iPads during the quarter, good for 68 percent of the market, as sales of Android tablets declined sharply. Amazon, which had captured 16.8 percent of the market in Q4 2011 with its Kindle Fire tablet, saw its share of the market fall to just 4 percent in Q1 2012, allowing Samsung to pass them for…