Update stripTypes transform to use fixed up jstransform transform

I've [updated](https://github.com/facebook/jstransform/pull/38) the jstransform transform that strips out types. Unfortunately, this transform can conflict with other transforms (the previous version had similar problems), so it needs to be run before the other transforms as a separate step. This PR finds the 3 places where we are doing transforms (jsx - offline transform, browser-transform.js - in-browser transform, syntax.js - test transform).

For the browser transforms, I added the convention that `stripTypes=true` enables the type stripping behavior (similar to `harmony=true`). 

Test Plan: 

1. `npm test`
2. Created a file with type annotations and ran `./bin/jsx --strip-types foo.js`
3. Created a bundle for the browser with `./node_modules/.bin/browserify vendor/browser-transforms.js > bundle.js` and made sure that script with `type="text/jsx;stripTypes=true;harmony=true"` was transformed.