Adds HelperError rescue class

The missing HelperError rescue class obfuscates the real problem or error should one arise in the web app.

For example, with the HelperError rescue class in place I can see this error:
<pre>
Redis::CannotConnectError at /
Error connecting to Redis on 11.22.33.44:6379 (ECONNREFUSED)
</pre>

But without the class I only see:

<pre>
NameError at /
uninitialized constant Oculusweb::HelperError
</pre>