FLUID-4907: updated class name map for contrast and text font.
FLUID-4907: Updated preference name to lineSpace

Changed preference name from lineSpacing to lineSpace in the primary builder. This is to match with the other components and will solve the issue where there was no default model for the lineSpace setting.
FLUID-5063, FLUID-4907: removed selections layer

Removed the selections layer from the rootModel. Updated unit tests for this change.