Fixed build script to use child_process.spawn instead of executive

- Maybe a node 0.10 bug?
- plus the code is simpler now
Stopped depending on "latest" jison.  This has burned me in the past
Fixed bug where C-style comments were too greedy

- This would parse as a nop:
    /* comment */ code /* more comment */
Merge pull request #6 from cspotcode/master

build.js fix(?), fixed greedy comments, and changed Jison dependency