Merge pull request #7 from jpalmieri/reorganize-test-module

renamed sign in  module and added it to Rspec config file
added conditions to sign_in and sign_out specs
moved user creation out of sign_in helper
added days_left to todos.
removed days_left row from todo, added as a method instead. Included days_left on todos#index
installed timecop
spec for todos destruction
rake task to destroy expired todos
changed rake task to reflect structure in blocitoff example
moved remove_outdated_todos to its own task spec