Unable to add multiple input bundles

[dudymas]

Given a bundle with more than one globspec:

cjsx_and_coffee = Bundle(
    '*.cjsx',
    '*.coffee',
    filters=['browserify'],
    output='js_all.js'
)

I expect for the browserify filter to run once, collect both cjsx files and coffee files, and return a single bundle as js_all.js.

Instead, I get a single output with the concatenated results of running browserify separately on each globspec:

(function e(t,n,r) function s .......

(function e(t,n,r) function s .......

This causes problems both in requiring files between globspecs and also produces an error on the page due to redefining methods.