COLOMBO (Reuters) - Sri Lankan lawyers boycotted courts on Thursday in protest at government attempts to fire the country's most senior judge, which they branded an attack on judicial independence. The United States, the United Nations and the Commonwealth have also raised concerns that the move to impeach Chief Justice Shirani Bandaranayake, on charges including financial irregularities and failure to declare assets, threatens the independence of Sri Lanka's courts. The Supreme Court has declared the impeachment attempt illegal. ...