Donald Trump's presidential campaign filed its first report with the Federal Election Commission on Thursday, providing a rare look inside the mogul's unusual political operation and revealing a campaign powered more by grassroots donors than the famous billionaire at its helm. Trump has stressed that he is willing to self-fund his campaign with up to $100 million, but through September, his campaign actually spent slightly more money from Trump supporters than from Trump himself. The filing shows Trump has invested $1.9 million of his own money into running for president, while his campaign spent $4.2 million this quarter, drawing from...