Add support for nyholm/psr7

[pyrech]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Related tickets	partially #103
Documentation	Todo
License	MIT

Add support for nyholm/psr7's factories.

[pyrech]

Is this PR wanted? I'm using my fork for now but it would be awesome if this PR could be merged and deployed soon! 😉
Thanks!

[Nyholm]

That is great. Thank you

[dbu]

i have a tiny worry here: should the new factories not be added at the bottom of the list? being first, if guzzle and nyholm are installed, the autodiscovery might switch what is found. if people really restricted themselves to PSR7, that will not matter, but maybe they relied somehow on guzzle being detected... is there a specific reason to put it on top? otherwise i'd prefer it at the bottom of the list.

[pyrech]

It was mentionned in the related issue. Nyholm is the lightest and the more complete PSR implementation. IMO it has its place as the recommended implementation to use by default

[Nyholm]

Changing the order is fine according to our bc promise: http://php-http.readthedocs.io/en/latest/httplug/backwards-compatibility.html

[dbu]

agreed!

thanks for the pull request @pyrech - and you are just too modest, @Nyholm, for not having added your own implementation :-D

[dbu]

@pyrech do you try this out in your project quickly, just so we are 100% sure its all fine? then @Nyholm or me can tag a new minor version.

[pyrech]

I'm already using my fork on production but will switch back to this package asap and ping here when done 😉

[pyrech]

Just tested it and it works 👍

[dbu]

thanks. i tagged 1.4.0 with this.