Pin down escodegen version due to the node-tar bug and huge esprima tarball problem.
Update dependencies and sort devDependencies alphabetically (by --save-dev)
Using jit-grunt
Update espower to 0.6.0
Big restructuring: embedded AST.

Now espower embeds target AST substree and tokens into output, and using subpath notation to point them.
Then empower accepts the subtree and pass them to formatter.
Merge pull request #9 from twada/embedded-ast

Big Restructuring: Embedded AST