[#461] Fixed the incorrect instructions for Mongo integration

Fixes #438, closes #461
Release 0.4.3
Added the `Tire::Configuration.pretty` option for JSON output

* The option is set to `true` by default
* Pass a truthy value to set the option to "true" or false/nil or false/nil to set the option to "false"
Added prettified JSON output for logging requests and responses at the `debug` level

Instead of displaying the request payloads and elasticsearch response as one lump,
use the `pretty` option in the JSON decoder/encoder by default:

    # 2012-09-21 17:29:47:506 [DELETE] ("articles")
    #
    curl -X DELETE http://localhost:9200/articles

    # 2012-09-21 17:29:47:508 [200]
    #
    # {
    #   "ok": true,
    #   "acknowledged": true
    # }

    # 2012-09-21 17:29:47:555 [CREATE] ("articles")
    #
    curl -X POST http://localhost:9200/articles -d '{
      "mapping": {
        "title": {
          "type": "string",
          "analyzer": "snowball"
        }
      }
    }'

    # 2012-09-22 10:43:58:851 [_search] (["logger-articles"])
    #
    curl -X GET "http://localhost:9200/logger-articles/_search?pretty=true" -d '{
      "query": {
        "query_string": {
          "query": "One"
        }
      }
    }'

To disable the default, set `Tire::Configure.pretty(false)`.
[TEST] Fixed bogus test failures on Ruby 1.8 due to Hash key ordering issues
[#334] Use `options.delete(:sort)` in model search to halt bubbling of `sort` into URL parameters

When the query is provided as hash, the params get concatenated, producing a query like this:

    curl -X GET "http://localhost:9200/graylog2/message/_search?from=0&page=1&per_page=100&size=100&sort=created_at+desc&pretty=true" -d '{"query":{"query_string":{"query":"*"}},"sort":[{"created_at":"desc"}],"size":100,"from":0}'

It produces an error:

    Parse Failure [No mapping found for [created_at desc] in order to sort on]

I don't know whether the other parameters should be there, as they're duplicated in the query, but at least they don't make the request invalid.
[#344] Add a test for 'sort' parameter in URL
[#334] Moved the test for `sort` option not bubbling into URL params to proper place

Closes #334.
[DOC] Fix lambda syntax for boolean queries in README.markdown

Closes #478
[TASKS] Fixed incorrect Rake task descriptions
[FIX] Fixed incorrect Rake import task

Closes #479.
[FIX] Use `MyModel.count`, not `MyModel.all.count` in the Rake import task

Previously, all records had to be loaded into memory (errr),
better to use the `Model.count` method

Closes #471
Improved the elapsed time reporting in the Rake task

Closes #480
[FIX] Remove `@options.delete` in Tire::Search::Search#to_hash so the call is not destructive

Closes #460.
Added the ability to define default values for Tire::Model::Persistence as lambdas

Now, it's possible to do:

    class MyModel
      include Tire::Model::Persistence

      property :created_at, :default => lambda { Time.now }
    end

Note though, that the lambda is evaluated when you create the object, not when you access the property.

Closes #459
Added `@search.results.max_score`

Closes #428.
Changed the URI escape/unescape compatibility patch to not require Rack

Originally by @joshreed, cleanup by @karmi.

Closes #384.
Removed unneccesary .gitignore entry, added "tmp"

Use "tmp" or "scratch" folders for things you wanna keep along the project,
but not version them.
[FIX] Added the ability to use the full DSL in filter facets

Previously, the `filter` facet type in Tire's DSL had the `terms` filter hardcoded.

With this patch, it's possible to use [any DSL method](https://github.com/karmi/tire/blob/master/lib/tire/search/facet.rb)
for the facet declaration.

See <http://www.elasticsearch.org/guide/reference/api/search/facets/filter-facet.html> for documentation.

Closes #425.
Add optional argument to all `to_json` methods as a defense against ActiveSupport

ActiveSupport, in many cases, calls `to_json` methods with arguments.

This patch adds optional argument to all `to_json` methods to guard against that.