Adding "|| exit 0" to prevent downstream failure in npm processes

[mattezell]

Various environmental or project scenarios may lead to a failure when calling lightercollective from postinstall. This is not known to be a lightercollective failure, but instead of a failure to properly call the lightercollective library. One such known scenario on Windows being multiple path casings being passed to child_process.spawn when npm-lifecycle processes postinstall.

Discussion on lifecycle/postinstall Win32 issue here: https://github.com/npm/npm-lifecycle/issues/29

This PR is intended to address this discussion: https://github.com/WebReflection/document-register-element/pull/165