add support for POSTing FormData objects with jQuery

I needed to be able to post Blobs created on the client. Either it's not supported or I am not familiar enough with Shred to get this working. However, I was able to get it working with jQuery. By modifying the processing of the body param to allow a FormData object to pass-through and letting jQuery process the multipart body, POSTing blobs is working.

Excerpt for API spec:
```javascript
...
{
    "method": "POST",
    "nickname": "importToDefaultSystem",
    "notes": "This will return a handle to the file upload.",
    "consumes": [
      "multipart/form-data"
    ],
    "parameters": [
        {
            "allowMultiple": false,
            "description": "The path of the file relative to the user's default storage location.",
            "name": "sourcefilePath",
            "paramType": "path",
            "required": true,
            "type": "string"
        },
        {
            "allowMultiple": false,
            "description": "The file upload request",
            "name": "body",
            "paramType": "body",
            "required": true,
            "type": "FileUploadRequest"
        }
    ],
    "summary": "Import a file via direct upload or importing from a url to the user's default storage location.",
    "type": "SingleRemoteFileResponse"
},
...
"FileUploadRequest": {
  "id": "FileUploadRequest",
  "name": "",
  "properties": {
      "fileType": {
        "description": "",
        "type": "string"
      },
      "callbackURL": {
        "description": "",
        "type": "string"
      },
      "fileName": {
        "description": "",
        "type": "string"
      },
      "urlToIngest": {
        "description": "",
        "type": "string"
      },
      "fileToUpload": {
        "description": "",
        "type": "File"
      }
  }
}
```

Example usage:
```javascript
data = new FormData();
data.append('fileToUpload', new Blob(['testing 123 456 789 10'], {'type': 'text/plain'}), 'testing123.txt');
data.append('fileName', 'testing123.txt');
Agave.api.files.importToDefaultSystem({sourcefilePath: 'path/to/upload/directory', body:data});
```