Added https support with Net implementation.

Added notion of default HTTP_CLIENT, to be able to build portable code among http client implementation.

library/network/http_client/tests/test-safe.ecf

@@ -10,6 +10,8 @@
 		<option warning="true" full_class_checking="true" is_attached_by_default="true" void_safety="all">
 			<assertions precondition="true" postcondition="true" check="true" invariant="true" loop="true" supplier_precondition="true"/>
 		</option>
+		<variable name="netssl_http_client_enabled" value="false"/>
+		<variable name="libcurl_http_client_disabled" value="false"/>
 		<library name="base" location="$ISE_LIBRARY\library\base\base-safe.ecf"/>
 		<library name="http_client" location="..\http_client-safe.ecf" readonly="false" use_application_options="true">
 			<option>
@@ -17,6 +19,19 @@
 			</option>
 		</library>
 		<library name="testing" location="$ISE_LIBRARY\library\testing\testing-safe.ecf"/>
-		<tests name="tests" location=".\"/>
+		<tests name="tests" location=".\">
+			<file_rule>
+				<exclude>.*libcurl_.*.e$</exclude>
+				<condition>
+					<custom name="libcurl_http_client_disabled" value="true"/>
+				</condition>
+			</file_rule>
+			<file_rule>
+				<exclude>.*net_.*.e$</exclude>
+				<condition>
+					<custom name="net_http_client_disabled" value="true"/>
+				</condition>
+			</file_rule>
+		</tests>
 	</target>
 </system>