OSLO (Reuters) - Norway's central bank kept its main interest rate unchanged at 1.5% on Thursday as expected and said the economy had developed largely in line with forecasts made in September.Norges Bank last month raised rates for the fourth time in a year amid solid domestic growth, but said further tightening was unlikely as the global economy gradually slows.All 35 economists polled by Reuters had expected rates to remain on hold ahead of Thursday's announcement, and only eight of those --..