Update README.md
Lock RSpec version to 2.14.

When starting development with the guard-jasmine gem,
the tests are failing because RSpec 3 gets installed, and the old RSpec
syntax (should, stub, etc) is being used in the tests.

This commit locks RSpec to 2.14 and can be removed whenever the upgrade
to RSpec 3 happens.
Runner as a class with options as an instance var

This converts the Runner module to a class with it's options stored
as an instance variable, which can be over-ridden on a per-run basis.

This is intended to simplify the runner code by removing the need to pass
the options to every single method.  It's also a first step towards
improving the logic of when a given message is hidden/shown in the runner.
Add specs for guard-reporter runner

Fairly minimal at the moment.  Will add further specs as reporter
is further developed
Move gems into gemspec

As pointed out by @lukeasrodgers in #168, it's a good practice
to have the gems listed as development dependencies in the gemspec
rather than in the Gemfile for gems.

However, I'm leaving the TRAVIS and rbx environments
in the Gemfile because I'm not sure of the best way to implement
that type of functionality in the gemspec
Upgrade specs to RSpec 3 format