fix default checkbox parameter bug
extract a private method to convert the input to boolean
Merge pull request #30 from zendesk/likun/fix_default_boolean_parameter

[APPS-1226] fix default checkbox parameter bug
add default readme for app template
update README.md
Merge pull request #33 from zendesk/dansun/add_default_readme

[PRI][WIP] add default readme for app template
Bump ZAS to v1.9.0