Prepare ezvis to a new version of castor-core

[parmentf]

Make ezvis use routes like /-/v2/browse /-/v2/display /-/v2/compute (v2 being the current version of castor-core: 2.x):

• [ ] create the routes in castor-core
• [ ] use them in ezvis

[parmentf]

The only files in ezvis containing these routes are asserts/js/dashboard.js and asserts/js/documents.js.

However, the /compute.json route is used from the ezvis settings:

    "$years": {
      "default": 0,
      "$?": "local:///compute.json?operator=distinct&field=Year",
      "parseJSON": true,
      "select": ".data ._id",
      "foreach": {
        "cast": "number"
      }
    },
    "$nbnotices": {
      "visible": true,
      "label": "publication(s)",
      "icon": "file-text-o",
      "$?": "local:///compute.json?operator=count&field=wid",
      "parseJSON": true,
      "get": "data.0.value",
      "cast": "number"
    },
    "$citations": {
      "default": 0,
      "$?": "local:///compute.json?operator=distinct&field=NbCitations&itemsPerPage=10000000",
      "parseJSON": true,
      "get": "data",
      "foreach": {
         "$$": {
           "$id": {
             "get": "_id",
             "cast": "number"
           },
           "compute": "id * value"
         }
       }
    },

we'll have to change the documentation accordingly:

• [ ] doc/Operators.md
• [ ] doc/CorpusFields.md
• [ ] doc/FlyingFields.md
• [ ] doc/Histogram.md
• [ ] doc/Display.md

[parmentf]

Although there seems to be a problem with exports in chart pages, it also seems that it is not from today. After investigation, it is independent from ezvis' code.