brushpicker and colorchooser dialogs refactor to singletons
removed unnecessary test
fixed tests
resolved conflict in BaseTool.java
throw IllegalStateException if ColorPickerDialog and BrushPickerDialog are not initialized
removed unnecessary comments
make singletons final
Merge pull request #44 from Catrobat/I40_color_picker_force_close

I40 color picker force close
Implementation: @galstc05 [sg]
Acceptance: @michaelmuenzer [mm]