Drivers beware.  Speed trap cameras will soon descend on iconic neighborhoods across Los Angeles including historic areas like Melrose, Hollywood and Sunset Boulevard, that will slap drivers with hefty fines.  About eight cameras will be installed in each district of the city, according to the Los Angeles Times , with a handful of other districts reaching more based on crash data and high-risk corridors.  Melrose Avenue from North Hayworth Avenue to North Orange Grove Avenue will now have a