Merge tag '0.2' into develop

hello world with screens
prepare TableView
controller handles data source table
simple tableView with datasource table
work with table the half way
refactoring spec, introduce categories model code
controller use model objects
finish model
Merge branch 'feature/tableview' into develop
refactor global _root to metarow.root
refactor local root access

also added missing template string in screen_spec
improve documentation
Merge branch 'release/0.3'