Shortens NormalizedParameterCollection to ParameterCollection.
Adds factory. Creates Server, Client, and KeyGenerators.
Updates test to use QueryAuth\Factory
KeyGenerator now accepts RandomLib\Generator as dependency
Changes 'add()' to 'set()'
Replaces strength key generator methods with single key generator method

Keys and secrets really should use the medium strength generator. By
changing the KeyGenerator constructor to accept a generator, a library
user could use a different strenght generator if they really want to,
but using the factory encourages use of the generator they should be
using.
Updates README
Updates composer.lock
Tests die with warning if 'composer install' hasn't been run
Moves RandomLib Factory and Generator mocks to KeyGenerator test
Removes mock helper methods
Updates test to use factory
Changes 'get' to 'new' for Factory methods that create new instances
Updates README
Merge pull request #8 from jeremykendall/pauls-suggestions

Updates encouraged by @pmjones at #cfn13