remove explicit window.debug export (#404)

Exporting to the "outer" scope of the module is more the responsibility
of the module loader (i.e. browserify, webpack, etc.) and thus this
is not necessary. `make test-browser` still passes after this patch.

Author: TooTallNate

src/browser.js

@@ -180,8 +180,3 @@ function localstorage() {
     return window.localStorage;
   } catch (e) {}
 }
-
-/** Attach to Window*/
-if (typeof window !== 'undefined') {
-  window.debug = exports;
-}