Case Insensitive Search

* Integrate VCR
* Add Glean::Source::Core specs
* Refactor Core.search and Contrib.search to use a Regexp
  * Add case insensitive search specs
String left Regexp right to match other conditionals
Only perform case insensitive search in case insensitive search context
Merge pull request #10 from simeonwillbanks/case-insensitive-search

Case insensitive search