Added Mode to allow Wallaby to pick up multiple ORM adaptors

1. Added concept Mode to allow Wallaby to pick up multiple ORM adaptors apart from ActiveRecord
2. Caching improvements:
   • Cached compiled ERB template (not for development)
   • Most Rails cache implementation for delete_match takes string instead of regex
   • Cached Calculations for finding a subclass
3. Resolve an issue when a file under /app folder is not following Rails convention (e.g. class CSV in csv.rb) or if it is a module declaration under concerns folder, it raises load error on booting up Rails server