Javascript episodic code generation

We can generate code without `-recurse` flag but the imports are not structured in a way to support episodic code generation, i.e., generated code imports the required modules from the current directory.

We can specify a node module path during compilation to use so we can import the modules that are generated from an included .thrift file from that module.

Example:

`A.thrift` has struct `A`

`B.thrift` includes `A.thrift` and uses struct `A`

`A.thrift` is compiled separately and packaged into `packageA`

When we compile `B.thrift` we specify path/to/packageA

`B_types.js` has the following import:

    `var A = require("packageA/A_types");`