President Barack Obama called it – in less than 140 characters, Reuters reports. Around 11:15 pm EST, just as the networks were beginning to call the race in his favor, Obama took to Twitter to proclaim himself the winner over Republican candidate Mitt Romney. “This happened because of you. Thank you,” Obama tweeted. That the president would take his message to Twitter before taking the stage in Chicago underscored the tremendous role social media platforms like Twitter played in the 2012 election…