#23 Create base components for UI elements

[Michael hall]

Create base elements that all UI elements will extend, such that they can be easily styled using reflection and displayed together inside other components.

Need:
QuestionPane (combine common functions from existing)
CompoundQuestionPane

QuestionTextPane (use and extend SonarTextPane)

ResponsePanes:
ResponseInputPane
ResponseTextPane
ResponseListPane
ResponseRankingPane
ResponseAllocPane
ResponseGridPane
ResponseScalePane

ListItemPanes: (use and extend ListItemButton)
ListItemTextPane
ListItemInputPane