Moves cell classes to subdirectory. Refs #39.
Moves scene controllers to subdirectory. Refs #39.
Renames nimrod files with n_ prefix. Refs #39.
Updates objc side to reflect nimrod sources change. Refs #39.
Updates tests to import new filenames. Refs #39.
Renames EHDB_vc to EHHistory_vc. Refs #39.
Silences debug log when API is used *correctly*. Refs #39.
Documents task in changes log. Refs #39.
Merge branch 'feature/t39_reorganise_sources'