Expose dev_compiler as npm module

[Aetet]

It will be extremely useful if dev_compiler will be exposed as npm-module too. It helps with integration with webpack, gulp and other tools. Here's an example for coffee

[ochafik]

DDC can now compile to node modules with the --modules=node option (including its sdk packages), but we don't package our runtime as a node module yet by default (should be addressed by #397).

If you want to test things out locally, have a look at tool/node_test.sh.