use legacy lodash in node environment

Using normal lodash will fail some tests in IE if the user is using
goinstant-assert within browserify.  This happens because if the tests
are built with browserify, lodash will be included via a `require` call,
rather than reading lodash off of the window.

Signed-off-by: Ian Livingstone <ianl@cs.dal.ca>
Merge pull request #11 from goinstant/bendecoste/use-legacy

use legacy lodash in node environment