Add hooks for Trial#choose! and Trial#complete!

This adds two new attributes to Split.configuration,
on_trial_choose and on_trial_complete.

Set these attributes to a method name available in the
same context as the ab_test method. These methods should
accept one argument, a Trial instance.

For example:

    Split.configuration.on_trial_choose = :log_choice

    # application_controller.rb
    def log_choice(trial)
      logger.info "experiment=%s alternative=%s user=%s" %
        [ trial.experiment.name, trial.alternative, current_user.id ]
    end
Add info to README about securing dashboard with Devise/Warden
Merge pull request #178 from swrobel/patch-1

Add info to README about securing dashboard with Devise/Warden
Update readme with trial event hook documentation
Merge pull request #176 from bmarini/trial-hooks

Add hooks for Trial#choose! and Trial#complete!
Updated rspec to 2.14 and fixed some deprecations
Version 0.6.3
Updated changelog
Added Rails Environment to Split Admin header
Merge pull request #187 from rceee/dashboard-environment

Added Rails Environment to Split Admin header
refactor dashboard js
Ensure request is defined before calling methods on it

In #is_robot? and #is_ignore_ip_address?, request is assumed to be
accessible. As a result, the Split::Helper module can only really be
included in a Controller context.

This commit removes that requirement by conditionally checking that
request is defined by attempting to call methods on it.
Merge pull request #190 from nfm/remove-dependency-on-request-in-split-helper

Ensure request is defined before calling methods on it
Fix travis issue
Merge pull request #188 from andrew/refactor-dashboard-js

Refactor dashboard js
Removed rails specific code from dashboard

Doesn't work outside of rails