Dollar in Broad Rally at Start of 2005  SINGAPORE (Reuters) - The euro and Swiss franc both fell  about 1 percent and the Japanese yen shed half a percent in  Asia Monday as the dollar rallied broadly in thin trade.   Holidays in Japan, Australia, New Zealand and London kept  volume low, exaggerating moves, and dealers said there was  nothing particular behind the dollar's rise.  "It seems to be position-squaring across the board in somewhat  thin markets. There is no major news or intervention or  anything like that," said David Simmonds, markets strategist  with the Royal Bank of Scotland.