doc(README.md): add README
feat(dreal.rb.template): add template
feat(update.sh): add update script
chore(.gitignore): add .gitignore
feat(.travis.yml): add travis-ci support
fix(update.sh): update
feat(README.md): add travis badge
feat(update.sh): build only needed
feat(update.sh): fix revision
feat(update.sh): add '-f' option