Acorn upgrade, eslint integeration

• code cleanup using eslint integeration.
• Upgrade acorn to support es6/es7.

adding gzip and broti size support

Merge pull request #2 from ajay2507/minify

adding gzip and broti size support

Bug fixes, support cli.

Minor bug fixes.
Support cli by using command lasso-unpack.

initial release

• Parse the lasso bundle and creates lasso-stats.json in your project structure.
• We can analyze the content and size of each file inside bundle.