Allow app properties in the imported/exported apps

[fcastill]

Initial support for app settings.

Will fix TIBCOSoftware/flogo#205

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[ ] bug report => search github for a similar issue or PR before submitting
[x] feature request
[ ] support request

Current behavior
App settings/properties are not supported in the UI but they are supported by the engine. Importing an app with settings will remove them during import.

Expected behavior
Importing an app with settings should be allowed, exporting the same app should keep the app settings.

Minimal reproduction of the problem with instructions

1. Import an app with settings
2. Export the app
3. Open the exported json, the settings are gone

• Flogo version: 0.5.4

Example app json:

{
  "name": "Properties",
  "type": "flogo:app",
  "version": "0.0.1",
  "appModel": "1.0.0",
  "properties": [
    {
      "name": "PROP_BOOL",
      "type": "boolean",
      "value": true
    },
    {
      "name": "PROP_DOUBLE",
      "type": "double",
      "value": 2.0
    },
    {
      "name": "PROP_INT",
      "type": "integer",
      "value": 2
    },
    {
      "name": "PROP_LONG",
      "type": "long",
      "value": 2
    },
    {
      "name": "PROP_STRING",
      "type": "string",
      "value": "This is string"
    }
  ],
  "triggers": [
    {
      "id": "receive_http_message",
      "ref": "github.com/TIBCOSoftware/flogo-contrib/trigger/rest",
      "name": "Receive HTTP Message",
      "description": "Simple REST Trigger",
      "settings": {
        "port": "9797"
      },
      "handlers": [
        {
          "action": {
            "ref": "github.com/TIBCOSoftware/flogo-contrib/action/flow",
            "data": {
              "flowURI": "res://flow:types"
            },
            "mappings": {
              "output": [
                {
                  "mapTo": "data",
                  "type": "object",
                  "value": {
                    "p1": "{{$.boolean}}",
                    "p2": "{{$.double}}",
                    "p3": "{{$.integer}}",
                    "p4": "{{$.string}}"
                  }
                },
                {
                  "mapTo": "code",
                  "type": "literal",
                  "value": 200
                }
              ]
            }
          },
          "settings": {
            "method": "GET",
            "path": "/get"
          }
        }
      ]
    }
  ],
  "resources": [
    {
      "id": "flow:types",
      "data": {
        "name": "Types",
        "metadata": {
          "output": [
            {
              "name": "string",
              "type": "string"
            },
            {
              "name": "integer",
              "type": "integer"
            },
            {
              "name": "double",
              "type": "double"
            },
            {
              "name": "long",
              "type": "long"
            },
            {
              "name": "boolean",
              "type": "boolean"
            }
          ]
        },
        "tasks": [
          {
            "id": "actreturn_2",
            "name": "Return",
            "description": "Simple Return Activity",
            "activity": {
              "ref": "github.com/TIBCOSoftware/flogo-contrib/activity/actreturn",
              "input": {
                "mappings": [
                  {
                    "mapTo": "boolean",
                    "type": "assign",
                    "value": "$property[PROP_BOOL]"
                  },
                  {
                    "mapTo": "double",
                    "type": "assign",
                    "value": "$property[PROP_DOUBLE]"
                  },
                  {
                    "mapTo": "integer",
                    "type": "assign",
                    "value": "$property[PROP_INT]"
                  },
                  {
                    "mapTo": "long",
                    "type": "assign",
                    "value": "$property[PROP_LONG]"
                  },
                  {
                    "mapTo": "string",
                    "type": "assign",
                    "value": "$property[PROP_STRING]"
                  }
                ]
              }
            }
          }
        ]
      }
    }
  ]
}