Add nb_handle_convert_to_var test

Also fix a few copy-pasta bugs in it
Fix coverage npm script
Add tmp package to dev deps
Cleanup some junk in test/c/test.js
Add -o options to bin/gen.py

Defaults to writing to stdout
Starting to make the generated JS match real code
Move test/js/module -> mod

This removes the name collision with node's module object.
Add Generated JS tests

* Add some properties to get function/types/tags counts
* Fix generated JS to use "mod" instead of "module"
Fix pnacl build of C tests
Add size to type.Record
Add more JS generator tests

* Add hack to correctly generate code for anonymous/unnamed structs
* Fix (?) gen.py's Type.__hash__ function
* Allow a record's size to be negative, if it is incomplete.
* Remove test/data/simple.h, and add generation from a string
* Add struct generator tests (from test/data/structs.h)
Add similar tests for unions
Add Generated JS tests for primitive types
Add simple shell scripts for running C/JS tests