HSEARCH-1346 Make Facet.count not part of Facet equality

Faciliates FacetManager.getSelectedFacets() / .getFacets() mixed usage
HSEARCH-703 Enabling queries for unindexed types with indexed sub-types
Preparing Readme and Changelog for 4.3.0.Final release
Set Maven pom versions to 4.4.0-SNAPSHOT
HSEARCH-1352 Clarify limitations of programmatic mapping not recognizing inherited properties

Documents limitation described in
 - https://hibernate.atlassian.net/browse/HSEARCH-1108
 - https://bugzilla.redhat.com/show_bug.cgi?id=947491
HSEARCH-436 Javadoc fixes and clarifications
HSEARCH-436 Code cleanup
HSEARCH-436 Moving LeakingOptimizer into the test util package of the engine module
HSEARCH-436 Deprecating getAllIndexesManager() and replacing it with getIndexManagerHolder()
HSEARCH-436 Replacing PropertiesMetadata with proper objects and extracting annotation scanning from DocumentBuilders