By Michael Holden and Kate Holton LONDON (Reuters) -Prince Charles paid an emotional personal tribute to his mother, Queen Elizabeth, on Saturday during celebrations to mark her Platinum Jubilee, praising the monarch for uniting the nation and continuing to make history during her 70-year reign. Charles spoke at a pop concert that opened with a comic sketch of the 96-year-old monarch having tea with Paddington Bear and tapping out the tune to the Queen anthem “We Will Rock You” on her china teacup. The heir-to-the-throne appeared towards the end of the concert at Buckingham Palace. As images o…