Renames Curl library hook to CurlRunkit.
Adds .gitignore file.
Implements first draft of an alternative to runkit overloading of curl functions.
Extracts duplicate code from CurlRewrite and CurlRunkit to \VCR\Util\CurlHelper.
Removes unnecessary code, adds documentation.
Merge pull request #6 from adri/feature/no-runkit-alternative

WIP: Draft of "no runkit alternative" for curl interception