- update documentation and project dependecies
- feature: Collection class has new method 'extend' that allow to concatenate two collections
- bugfix: invalid return type annotation in Collection methods
- bugfix: Collection::getElementMovedByOffset is not throwing exception for non-numeric (indexed) collection
- update phpdoc comments
- modify: one element collection will now support isset method
- feature: new
getBy
method added to Collection to retrive collection of entities matching criteria defined in callback