Countrywide Financial remained the top servicer in the residential mortgage market at the end of the first quarter of 2005, according to a new ranking and analysis by Inside Mortgage Finance. Countrywide reported $893.4 billion in mortgage servicing as of the end of March, a 6.6 percent increase in just three months. That gave the company a 10.8 percent share of the estimated overall market of $8.30 trillion, up from the 10.6 percent market share…