Replace file_get_contents() with Curl

- Replace file_get_contents() with Curl because Curl is faster and
  file_get_contents() is disabled on a lot of servers for security
  reasons.
- I also notice Curl getting a lot of results back from
  websites where file_get_contents() didn't work.
Merge pull request #8 from MitchellMcKenna/feature/replace-file_get_contents-with-curl

Replace file_get_contents() with cURL for speed/security