Fix test-jasmine on windows

[Hypercubed]

Two issues were preventing npm run test-jasmine on windows:

1. karma-browserify had a bug (See fix(preprocessor): use full path to temp dir for browserify-bundle pr… nikku/karma-browserify#154, fixed by bumping to karma-browserify 4.4.1).
2. On windows (or cygwin) paths generated by the requireTransform browserify transform contain platform-specific file separators (fixed by converting file separators).

[Hypercubed]

See #29

[etpinard]

@Hypercubed Beautiful. Thanks so much for doing this.

FYI: we're fighting some test randomness issues on CircleCI, rebuilding your test run was enough to get the tests to pass.