Add checkbox, radiobutton, radiobuttongroup element interfaces
Merge remote-tracking branch 'upstream/master' into darcy-ui-i18-fundamental-ui-element-types

Conflicts:
	src/main/java/com/redhat/darcy/ui/Elements.java
Add Checkbox#check and Checkbox#uncheck
Merge branch 'master' into darcy-ui-i18-fundamental-ui-element-types
Rename RadioButton and RadioButtonGroup interfaces
Refactor RadioGroup interface
Revert RadioGroup interface
Remove RadioGroup interface for now
Or at least I thought it was removed
Add DateSelect and MultiSelect interfaces, update Elements static factories
Update DateSelect to use Java 8 LocalTime api, update MultiSelect to not use Optional in List returning methods
Rename DateSelect to DateInput, add #toggle method to Checkbox interface
Update method names in Elements to correct names (DateInput)
Merge remote-tracking branch 'dmcneil/darcy-ui-i18-fundamental-ui-element-types'

Conflicts:
	src/main/java/com/redhat/darcy/ui/Elements.java