Parameterhandler add json support

[benjamin-carl]

Hi Christophe,

I've been using your library in a Symfony context for a longer time, loved it cause of its simplicity - so btw thanks for it! I required something similar in a different context and with JSON support. So I've forked your project and added support for JSON while keeping everything else as untouched as possible ;)

I've re-adjusted some directoy layouts to provide a similar test stcuture for example and fulfilled all existing tests for the JSON part.

I'm pretty sure that it will be very helpful for other developers as well and so I hope you're willed to merge my addition. Yes I know - it's a huge PR and contains a lot of changes - but all tests running successful. So lets see the Travis build results for other PHP versions ...

Ben

[OskarStark]

WOW, what a huge PR 👍

@clickalicious i think you should provide an UPGRADE path, because there are some BC breaks in your PR

[benjamin-carl]

Can you please explain what UPGRADE path you refer to @OskarStark.

Indeed I've missed to look at the existing PR's and a merge would break those. A possbile upgrade path would contain the merge of existing accepted PRs and I readjust some parts of my work afterwards.

So the UPGRADE path should contain the merge of existing PRs and i realign everything based on the result. Currently I can't imagine how many of the 17 open PRs are going to be merged into the codebase.

From outside view my PR does not break any existing functionality but providing an additional format.
I changed the way how the ScriptHandler calls the YamlProcessor or JsonProcessor. This way contains the creation of instances in a loop so it have some negative but from my pov irelevant impact on performance. In result it would be possible to mix dist file formats in one project/execution.