Extending Dates Role's Vague String handling & Fixing #346

I've extended the handling in order to support the functionality required to fix https://github.com/duckduckgo/zeroclickinfo-goodies/issues/346

It "shouldn't matter"... on the other hand, we don't explicitly set the timezone, so we should probably either settle on 'UTC' or 'user local with UTC fallback' just in case we hit a server (poorly) configured with a local clock.

@mintsoft I'll defer to your judgment on this.