Release TinyECS 0.3.0 [Fix appveyor.yml]

Changes:

* A components iterator that provides easy way of enumerating over all
components that some entity has

* Add custom debug inspectors for WorldContextsManager, EntityObserver
and SystemManagerObserver types

* Implement ToString() method for Entity type

* Add template project for Unity3D and corresponding tutorial sample,
which demonstrates how to integrate TinyECS into Unity3D

* Fixed an issue "Created with GameObjectFactory entities don't have
TViewComponent attached to them" #11

* Fixed an issue "Reactive systems don't response on to events that are
generated with IUpdateSystem implementations" #6

* Now all reactive systems are executed after all IUpdateSystems

appveyor.yml

@@ -1,6 +1,6 @@
 image: Visual Studio 2017
 
-version: 0.2.{build}
+version: 0.3.{build}
 
 platform:
   - 'Any CPU'