Thanks to Marco Hermo and Brett Tasker for helping with this
* Bump framework/cms to ^4.0@dev
* WIP Silverstripe 4 compatibility fixes
* more replacements and patches to migrate this module to 4.0
* Update composer.json
* remove php <5.5 from travis.yml
* WIP more SS4 compatibility fixes
* WIP fix solr path to use DIR, avoid hardcoded module name
* WIP respect current include path
* WIP Namespacing and use on SearchIndex class
* Namespacing for tests
* WIP add namespaces to all classes
* Second push of Test changes + namespacing
* WIP split Solr files with multiple classes into single file / single class. Adjust namespaces
* Fix PHP errors in test
* break out search components with multiple classes into individual files and change namespaces
* Update namespacing for Search indexes and variants in tests
* Batch fixes for tests #2
* Update _config.php to use namespace
* Use root namespace in referencing Apache_Solr_Document
* Migrate task names so that the name is not fully qualified
