Add _urlIsWhitelisted to notifier

If hostWhiteList config option is set, check the payload’s frames and
filenames to verify that they have been whitelisted. Ignores “unknown”
filenames.

Add missing UNKNOWN_FUNCTION and computeStackTraceWrapper
They were not fully cleared from the codebase, so adding them back in
from a previous beta release for now.

Add missing setupCustomJSON

Pulled from previous release. Just copy/paste without looking. Living
on the edge. More specs passing because of this.

Expand on "unknown error" message.
Remove submodule methods, update js style
Remove 'done' callback from whitelist tests

Not needed. Thanks, @alan-andrade.
test multiple whitelisted domains
Reverse regex logic against whitelist

As per @coryvirok's comment.
Cleaned up variable grouping, and added some short-circuilt logic to
make code more clear.
Stop whitelisting "unknown" by default
Merge pull request #31 from cfurrow/whitelist-domains

Add ability to whitelist domains via .configure()