Support persistent connection, even in single thread mode (i.e concurrency=none).

Warning: as there is no concurrent request handling in single threaded mode,
            it is recommended to either set the keep_alive_timeout to a small value,
            or disable persistent connection by setting max_keep_alive_requests to 0.
Change the default keep_alive_timeout from 15 to 5 seconds.
Accept -1 as value of max_keep_alive_requests to have unlimited number of request in the same persistent connection.

examples/websocket/websocket_app.ecf

@@ -3,9 +3,9 @@
 	<target name="websocket_app">
 		<root class="APPLICATION" feature="make_and_launch"/>
 		<file_rule>
-			<exclude>/\.svn$</exclude>
 			<exclude>/CVS$</exclude>
 			<exclude>/EIFGENs$</exclude>
+			<exclude>/\.svn$</exclude>
 		</file_rule>
 		<option warning="true">
 			<assertions precondition="true" postcondition="true" check="true" invariant="true" loop="true" supplier_precondition="true"/>
@@ -17,6 +17,14 @@
 		<library name="wsf" location="..\..\library\server\wsf\wsf.ecf"/>
 		<cluster name="app" location=".\" recursive="true"/>
 	</target>
+	<target name="websocket_app_st" extends="websocket_app">
+		<description>Single thread solution. 
+			Warning: as it can not handle concurrent request, it is recommended to set Keep-Alive-Timeout to very low value, as browser will keep persistent connection open too long.
+		</description>
+		<capability>
+			<concurrency use="none"/>
+		</capability>
+	</target>
 	<target name="websocket_app_ssl" extends="websocket_app">
 		<variable name="ssl_enabled" value="true"/>
 	</target>

examples/websocket/ws.ini

@@ -2,11 +2,11 @@ verbose=true
 verbose_level=INFORMATION
 port=9090
 max_concurrent_connections=100
-keep_alive_timeout=35
+keep_alive_timeout=2
+max_keep_alive_requests=-1
 max_tcp_clients=100
 socket_timeout=30
 socket_recv_timeout=5
-max_keep_alive_requests=300
 
 is_secure=false
 secure_certificate=ca.crt