Bungary's opposition party Tisza is on track to win a two-thirds parliamentary majority in Sunday's election, allowing it to amend the constitution and key laws needed to unlock EU funds, a projection from polling agency Median showed on Wednesday. Veteran nationalist Prime Minister Viktor Orban and his Fidesz party are facing the biggest challenge to their rule in 16 years as the centre-right Tisza party, led by Peter Magyar, is leading in independent polls. Tisza is seen winning between 138 and 142 seats in the 199-member parliament, according to an estimate based on an analysis of Median's five most recent...