radiobuttons support
refactor widget callbacks out into a separate file
refactor button widgets into internal lTerm_buttons_impl module
add .merlin file for merlin tool
add generated documentation to .gitignore
cleanup lTrem_widget documentation
cleanup lTerm_buttons_impl
add usage of radiogroup#switch_to to radiobuttons example
Update _oasis

Update oasis version from 0.3 to 0.4
Change 'License:" to 'BSD-3-CLAUSE'; otherwise oasis complains about
'BSD3' being obsolete.
better example of resource file
rearranged doc comments placement for consistency
Merge pull request #8 from avysk/radiobuttons

Radiobuttons