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

@mintsoft We're not doing much which is very time sensitive.  The biggest problem may be people doing descriptive date strings around the end-of-year/end-of-month.  I think it's ok, but I again defer.