Revert 'require' word optimization

@zertosh What do you think about reverting the regex optimization so that syntax-error can be removed upstream?

Giant libraries with no require calls should be noParse'd anyway, and the performance difference, while significant, is only really marginal. Whereas the performance difference gleaned by removing syntax-error upstream is asymptotic and enormous.

IMO the bundle time of incremental re-builds is more important than one off full rebuilds, since incrementals are executed constantly (and also could be cached by browserify-incremental if you wanted).

I'm requesting this per your comment in this thread:

https://github.com/substack/node-browserify/issues/1208#issuecomment-92146245

If you did this and merged in your sm-fast branch, we could have really awesome rebuild times I think.

Start by locating the regex optimization discussed in the issue and trace how it relates to syntax-error. Read the referenced browserify issue and compare the sm-fast branch mentioned there. Done means the optimization is reverted in a way that supports removing syntax-error upstream, with the project's existing checks still passing.

Written by the indexing model from the issue text.