Close resources to stop Apache lib from pending

[sebr72]

Fix issue where you no longer get a reply after 5 requests with:
` try (CloseableHttpClient client = HttpClients.createDefault()) {
HttpUriRequest request = new HttpGet("https://map.geo.ti.ch/oereb2/image/symbol/ch.Nutzungsplanung/legend_entry.png?identifier=423441325078");
HttpContext context = null;

        for (int i = 1; i < 7; i++) {
            System.out.println("i = " + i);
            HttpResponse response = client.execute(request, context);
            System.out.println(response.getReasonPhrase());
        }
    }

`

See JIRA issue: ISSUE-36.

[sbrunner]

Thanks :-)

[sebr72]

This PR is followed by issue 39