Add no-store to Cache-Control setting.

This fixes the following issue:

Given I am using Chromium 33
And my Rails app is using both rack mini profiler 0.9.1 and wiselinks
1.2.0
And the app has a wiselinks-enabled link in some page A that loads
another page B via ajax
And the app has a another link which is not wiselinks-enabled
When I go to page A
And I click on the page B link
Then page B will be loaded via ajax in page A
When I click on a link that is not wiselinks-enabled
And I return to page B with the back button of the browser
Then I will see page B without any layout

Cause: wiselinks sets Cache-Control to 'no-cache, no-store, max-age=0,
must-revalidate
(https://github.com/igor-alexandrov/wiselinks/blob/e473ebd81addf613e175ba729be68ae7834b2c37/lib/wiselinks/rendering.rb#L14).
However, rack-mini-profiler removes the no-store value when it sets
Cache-Control to 'must-revalidate, private, max-age=0'
(https://github.com/MiniProfiler/rack-mini-profiler/blob/734c8a5d47b0a4ce3a1d07e5fe3c6aa64dee548e/lib/mini_profiler/profiler.rb#L378).
According to
http://stackoverflow.com/questions/16173322/google-chrome-does-not-revalidate-etag-on-back-forth,
this allows Chrome to reload the wiselinks partial response when using
the back button.
Merge pull request #69 from lovewithfood/with_no_store_cache_control

Add no-store to Cache-Control setting?