Update script for compatibility with PHP CompatInfo v4.0.0

Summary:
The API for PHP CompatInfo changed significantly in v4.0.0 and therefore this script needs to be updated. One of the major differences is that the data is now stored in an SQLite database and JSON files rather than in PHP source code.

Another noticable difference is that the newer version is missing information regarding the compatibility of class methods. I have filled an upstream issue for this, but I don't consider this to be hugely significant as they data isn't currently used.

I also took this opportunity to tweak the output format to include some additional fields (although I have no immediate plans to use these fields).

Test Plan:
Eyeballed the output. The main thing that looked out of place was the following, which seems wrong to me:

"opcache_compile_file": {
  "min": "5.2.0",
  "max": null,
  "ref": "Zend OPcache"
},
"opcache_is_script_cached": {
  "min": "5.2.0",
  "max": null,
  "ref": "Zend OPcache"
},

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D12278