Britain's closest election in a generation goes down to the wire

By Andrew Osborn LONDON (Reuters) - Campaigning in Britain's most unpredictable election in a generation entered its final day with the two main parties level in most polls and neither on track to command a majority in the parliament of the world's fifth largest economy. Despite five weeks of campaigning, neither Prime Minister David Cameron's Conservative party nor Ed Miliband's opposition Labour has a clear lead, teeing up a potentially messy and uncertain outcome after Thu