By Alistair SmoutLONDON (Reuters) - Scotland's leader Humza Yousaf resigned on Monday, further imperilling more than a decade of governance by the Scottish National Party (SNP) and setting back its aspirations of independence from Britain.The crisis marks a stunning fall for the SNP and strengthens the hand of the UK opposition Labour Party ahead of a national election expected this year. HOW DID THE SNP GET HERE? The party achieved majority government in Scotland in 2011, leading... Read this story