Samsung is knocking off the top players in mobile. First, they ousted Nokia to become the top mobile phone vendor in the world for Q1 of 2012. Then they pushed passed Apple to become the most prolific smartphone manufacturer. Overall, phone sales were down year-over-year by 1.5% but smartphone shipments are up 42.5%. “The race between Apple and Samsung remained tight during the quarter, even as both companies posted growth in key areas,” said Ramon Llamas, senior research analyst with IDC’s Mobile Phone Technology and Trends program. “Apple launched its popular iPhone 4S in additional key…