Update packer.py
Update packer.py

updated to handle string begin and end properly
beautify-web/js-beautify,beautify-web/js-beautify,bitwiseman/js-beautify,beautify-web/js-beautify,bitwiseman/js-beautify,beautify-web/js-beautify,bitwiseman/js-beautify,bitwiseman/js-beautify