[PoC] Button Group

This add s button group which accepts multiple buttons and prints them as bootstrap expects them.
More improvements, tests and cleaning up are needed.

Also there is an issue with whitespace, since bootstrap relies on it to add space between buttons, used a nbsp for now.
Further work

- added tests
- added check for only accepting buttons
Renaming formt type to FormActions, to avoid confusion with button groups.
Removed left over short array syntaxes.
Fixing block names in template.
Merge pull request #182 from rdohms/button-group

Support for Form Actions (grouped buttons)