Well, Trump has been saying the elections were rigged or a sham since at least 2012. No matter how he lost, he was never going to accept the outcome.
Here are Trump's tweets after Romney lost to Obama in 2012 (note: Trump made these tweets before he realized that Obama had also won the popular vote):
Sounds familiar doesn't it?
Trump calling for a "revolution" because he thought Obama won the electoral votes but lost the popular vote (which was false -- Obama won both.) Any one who thinks Trump is a conservative needs to read Article II section 1 of the U.S. Constitution. Then, you have Trump in 2016 losing the popular vote to Hillary, but winning the electoral vote...