JdkRequest does not support compression

[andreoss]

Add support for gzip and deflate and enable this tests:

jcabi-http/src/test/java/com/jcabi/http/RequestITCaseTemplate.java

Lines 180 to 195 in 9f069cf

	@Test
	@DisabledIf("isJdkRequest")
	final void readsDeflatedJsonResponse() throws Exception {
	MatcherAssert.assertThat(
	"Must undeflate & parse Json response",
	this.request("/deflate")
	.fetch()
	.as(JsonResponse.class)
	.json()
	.readObject(),
	Matchers.hasEntry(
	Matchers.is("deflated"),
	Matchers.is(JsonValue.TRUE)
	)
	);
	}

jcabi-http/src/test/java/com/jcabi/http/RequestITCaseTemplate.java

Lines 197 to 213 in 9f069cf

	@Test
	@DisabledIf("isJdkRequest")
	final void readsGzippedJsonResponse() throws Exception {
	MatcherAssert.assertThat(
	"Must unzip & parse Json response",
	this.request("/gzip")
	.fetch()
	.as(JsonResponse.class)
	.json()
	.readObject(),
	Matchers.hasEntry(
	Matchers.is("gzipped"),
	Matchers.is(JsonValue.TRUE)
	)
	);
	}