Adds rbEnv configuration files

Specifies ruby 2.1.2 and gemset 'flat'
Updates project README; specifies project homepage in gemspec
Adds and configures RSpec, Guard and Pry to the project

Development dependencies, also specified their versions in the gemspec
Adds TravisCI configuration
Adds Coveralls support to the project
Adds Coveralls Badge to README
Adds TravisCI badge to project README
Adds gemspec summary and description; Sets version to 0.0.0 to indicate a WIP gem
Replaces first TODO in README
Starts to define general file layout

Going for a modular approach this is the start of grouping functionality into separate files.
Fixes the requires in Flat::FIle
Moves flat_spec to spec/lib; Adds nonsense comments to Flat to ensure Guard is working
Redefines bundler dependency to get TravisCI building the project
Adds small note about previous bundler dependency definition
Adds runtime dependency on extlib; Starts to add documentation
Adds develop branch Coveralls badge [ci skip]
Adds RDoc generation to the project
Specifies a simple USAGE example in the README; Continues to add documentation to Flat and Errors
Continues to expand documentation of Flat
Removes file folder; Expands documentation on Layout