Added help message for when no command is specified
Created an Email object constructor and accessory objects

- To reduce the significant code duplication between commands, decided to make Emails into their own objects and abstract away a lot of the repetitive argument parsing and email existence checking

- Created a constructor for Email object creation, and two accessory object creators (EmailHelper and EmailArgumentParser) to handle associated responsibilities of Email creation
Merged the EmailArgumentParser and EmailHelper objects

- The functionality of these objects were closely related enough (all to do with Email object construction) that it made more sense to merge the constructors and have a single EmailHelper object
Updated the Build submodule to work with the new Email objects

- Also modified the build command to accept multiple arguments
Updated EmailHelper logging (added warnings about non-existent emails)
Updated the Sass Compiler submodule to use Email objects

- Also updated the sass command to accept multiple arguments
Typo fix (whitespace)