Guzzle

[benallfree]

A small update to introduce Guzzle support rather than raw curl. This feels more reliable to me and also fixes a couple bugs in createFromUrl:

1. The old implementation saved responses even when they were not 200 HTTP status
2. The old implementation loaded the whole response into memory before saving. This saves directly to file, far more memory efficient.

These can be accomplished with raw curl too, but I felt Guzzle modernized things a bit and made the process more reliable. Guzzle also supports environments without curl.

[benallfree]

Bad push