adds spec_helper to require all files, adds helper method
adds specs for sorting functionality

utilizes #test_records defined in spec_helper
Updates method name
Updates method name #to_output to #format
Removes Sorter class

Sorting functionality has been added to the Records class
in order to condense knowledge of Records objects and its internals
in one place
Adds Records class to model collection of Records

The Records class is responsible for holding multiple records
and the behaviors associated with such collection. I.E. sorting and
adding a record or multiple records.
Changes method name #to_output to #format

this method
adds file to require all other files

This reduces the number of 'require' statements in other places
Implements CLI interface for RecordManager

- Utilizes standard OptionParser library to parse flags
- '-s TYPE' sorts records via type ('gender', 'last_name', 'birthdate')
- Not providing TYPE option defaults to sorting by 'last_name'
- Can load one file or multiple files