Added basic test for TimberQueryIterator

TimberIteratorTest::testTheLoop simply shows how a template tag like 'get_the_title' can now be used in a template file. In the test, replace 'Timber::query_posts' by 'Timber::get_posts' to get an array (like the old behaviour) and see the test fail.
merged @mgmartel's work into new TimberPostGetter
merged work on 5f9019a703595c37399866253abf89f5b9100215. Using Iterator to return posts
Remove next() implementation in TimberQueryIterator
Don't create yet another object if given object is already of the right type
Let the unit test use the result of Timber::get_posts as an Iterator instead of as an array
merge of 67aaee72e7b5a4907699ae4b2ac5a62f25e1d962
Implemented get_posts on TimberQueryIterator, that either returns the plain TimberPosts array, or the TimberPostsCollection
allowed get_posts to wrap query_posts from commit ee3e123664c1e8f07f8d470fb1c5d04d7f7e55a4
merge of 44fa705c0aa03fd95e7979d40b17c2485d3205db, should take the $PostClass into account
remove bad merge in timber.php with handle_post_results
resolved merge of 490510a3b88b02d1ed2847da199e133643bc1d7d
Restore unit test from 4ba7c09 now that get_posts returns an array
Implement getting posts from slug with hash and post type
(almost) all tests passed....
issues are resolved except for post previewing
remove extra error log
removed unneeded code based on presence of Query
wrote test to verify that you can still get a post by the slug
removed very old url_to_path method. Complies with WP coding standards