ParserParameterProcessor to support JSON typed annotation

[mwjames]

This PR is made in reference to: #N/A

This PR addresses or contains:

• This allows to add JSON typed annotation in the #set and #subobject parser function using the @json marker.
• Using the JSON format allows for creating structured annotation by means of electronic generators
• A depth of 3+ is not supported (for details see test cases)

{{#set:
    |@json={
    "foo": [
         "bar",
         "foobar"
    ]
}
}}

This PR includes:

• Tests (unit/integration)
• CI build passed

[mwjames]

http://sandbox.semantic-mediawiki.org/wiki/Issue/1891

[mwjames]

@kghbln FYI

[mwjames]

Using the | pipe symbol generally posses an issue within a parser function when used as part of the content representation and to avoid breaking the content +pipe can be used to signal that no breakage is expected for the preceding element (well, internally we clue the content together since the MW parser would split the content no matter what).

{{#set:
    |@json={
    "has text": "Some text with a | pipe symbol ..."
}|+pipe }}

{{#subobject:
    |@json={
    "has text": "Some text with a | pipe symbol ..."
}|+pipe }}

Just to clarify on how +pipe works, MW's parser would produce something like:

array(4) {
  [0]=>
  string(0) ""
  [1]=>
  string(41) "@json={
    "has text": "Some text with a"
  [2]=>
  string(25) "pipe symbol ..."
}"
  [3]=>
  string(5) "+pipe"
}

Since +pipe indicates the usage of | and knowing the convention by means of MediaWiki, we can concatenate the string without the split yet with one exception that we don't know whether the text before and after | contained trailing spaces or not (MW's parser removes spaces). The processed text will appear as Some text with a|pipe symbol within ... instead of the Some text with a | pipe symbol within ...

PS: I did forget to add them to the integration test, so it would be nice if someone could extend the test.