A suspect in the murder of a pregnant woman in Hoover was arrested, police said.  U.S. Marshals and police took 29-year old Brian Epps into custody, at a home in Bessemer late Tuesday night.   Epps is facing a capital murder charge in the shooting death of his wife Rashon, who was expecting the couple's baby, investigators said.  She was gunned down Saturday, outside her apartment on Warringwood Drive.     Friends said the couple was having marital problems.