small fix to RNPageSwipe
Implemented setScissorRect (w/ examples) to RNObject, RNText, RNBitmapText, RNButton, RNGroup, RNMap, RNPageSwipe, and RNListView.
Added missing setScissorRectangle to RNText.lua
Merge pull request #99 from Sylph/rapanuidev-scissorRect

Implemented setScissorRect (w/ examples)
updated contribution readme
fix to RNGroup scissor rect
Added lunatest sources to rapanui-test
Create new layer and add it to the viewport
Layer can be get by name
Cannot create new layer with same name
Create layer with partition
Layer can be deleted and the container is properly cleared
All layers can be removed with removeAll
Tests for RNScreen initWith
Return also partition when creating new layer with partition
RNScreen now uses RNLayer to create the main partition and the layer
Main layer name is create from RNLayer constant MAIN_LAYER
Unit tests for addRNObject
refactored mock objects from RNSceenTests to own files
refactored mock objects from RNLayerTests to own files