Bump PHP7 version and PHPUnit

[simPod]

Let's bump PHP to secure supported version. So we can make further improvements to the lib without pain. Eg. see #774. There is v0.4 released with PHP5 support so should be no deal to consumers.

I tried to keep changes at minimum but eg. it's impossible to decently test code with ini_get/ini_set so I had to do small modifications (see Changelog).

[simPod]

@cboden answering #774 (comment) here as it's related to this PR.

It was impossible to write tests for it properly when code relied on ini*()_ calls.

Tests throw ini_set(): Headers already sent. You cannot change the session module's ini settings at this time so I figured we should not use these in tests.

[cboden]

I see. In that case I think it would be best to alter the SessionProvider constructor signature to make add OptionsHandler to the end and make it an optional parameter (see how $serializer is done). This will prevent a BC break.

[simPod]

What about now

[cboden]

Tests are failing 😬

[simPod]

Run them locally and passed. Dunno why travis installs symfony/routing v5 when constrain is ^2.6|^3.0|^4.0

Rebasing on current master and fixing.

[patrickbussmann]

Its very useful. Thanks!

[simPod]

@cboden hi, do you have any further comments?

[cboden]

Hey @simPod. Thank you for your work on this and my apologies for my delayed response.

We think we're going to use your PR as a base for v0.5.

One small change request: could you move the OptionsHandler code to our Session namespace please? Since it's not used outside Sessions and it's a requirement for Sessions I don't think we need it more widely scoped.

[simPod]

done

[mbonneau]

Looks good to me! Thanks for PR @simPod .

[cboden]

Looks good. A couple tiny comments. Thank you for all your hard work @simPod