Add commands to load the data into memory for later re-use

I'm using this in our project for running our cucumber suite. For now it's a little dirty but I'm using it like this. This is much better than what I was doing before which was to rebuild the search index data from the database data which is much slower.

```ruby
Search::Placement.index.delete

# Fetch the search index data from file and load it in memory
FixtureLoader.search_loader = EsDumpRestore::App.new
FixtureLoader.search_loader.load_data(Tire::Configuration.url, 
                                  'test_search_placement', 
                                  "#{Rails.root}/test/fixtures/search.tgz")
FixtureLoader.search_loader.recreate!
```

Then I created a tag and after hook to refresh the search data during test runs.

```ruby
After('@changes_data') do |scenario|
  # rebuild the search index from fixture data
  Search::Placement.index.delete
  FixtureLoader.search_loader.recreate! 
end
```