Simplify null checks with PHP 5.3 syntax
Property constructor parameter is optional
Merge pull request #308 from wmde/isOptional

Simplify null checks with PHP 5.3 syntax
Merge pull request #309 from wmde/slOptional

Property constructor parameter is optional
Fix StatementList not reindexing associative arrays
Merge pull request #311 from wmde/slKeys

Fix StatementList not reindexing associative arrays
Add language filter method to TermList

The deprecated getLabels and getDescriptions methods in Entity have an optional
filter parameter. This provides a cleaner and non-deprecated way to do such
filtering.
Bump to 2.5 alpha
Add language filter method to AliasGroupList
Merge pull request #313 from wmde/langfilter

Add language filter method to TermList
Update RELEASE-NOTES.md
Add extra convience methods to SiteLinkList
Merge pull request #318 from wmde/ssl

Add extra convience methods to SiteLinkList
Update RELEASE-NOTES.md
Add GUID to constructors