Merge branch 'master' into develop
bump version for development
split versions before checking if installed
use `git pull` to update work tree.

`git reset --hard` will not update work tree if the `revision` is a ref.
*EXPERIMENTAL* implement form validation
refer a jelly variable of `rootURL` from erb template
return form validation result as hudson.util.FormValidation
add validation for PYENV_ROOT
update TODO.md
Merge branch 'form-validation' into develop
update gem dependency versions
add `require "java"` in model defs
v0.0.4
Merge branch 'release-0.0.4'