adding preference option for dynamic input blocking

/inpblock is now having subcommands 'timeout' and 'dynamic'
with:

/inpblock timeout <milliseconds>

and

/inpblock dynamic <on|off>

Defaults are:

/inpblock timeout 500
/inpblock dynamic on

To get the old behavior specify:

/inpblock timeout 20
/inpblock dynamic off

The dynamic mode will block incrementally after something
should be written to the window or after a key was pressed. So pressing
a key would set the timeout to 0ms and after 10 timeouts to the next
bigger one.

Example (with dynamic mode on):

"/inpblock timeout 50"

timeout series:

10x 0ms
10x 10ms (0ms + 10 times since last keypress)
10x 30ms (10ms + 20 times since last keypress)
*x50ms until next key was pressed or

src/ui/console.c

@@ -1182,7 +1182,12 @@ cons_show_chat_prefs(void)
 void
 cons_inpblock_setting(void)
 {
-    cons_show("Input block (/inpblock)       : %d milliseconds", prefs_get_inpblock());
+    cons_show("Input timeout (/inpblock)     : %d milliseconds", prefs_get_inpblock());
+    if (prefs_get_boolean(PREF_INPBLOCK_DYNAMIC)) {
+        cons_show("Input dynamic (/inpblock)     : ON");
+    } else {
+        cons_show("Input dynamic (/inpblock)     : OFF");
+    }
 }
 
 void

src/ui/core.c

@@ -206,6 +206,11 @@ ui_input_nonblocking(gboolean reset)
     static gint timeout = 0;
     static gint no_input_count = 0;
 
+    if (! prefs_get_boolean(PREF_INPBLOCK_DYNAMIC)) {
+        inp_non_block(prefs_get_inpblock());
+        return;
+    }
+
     if (reset) {
       timeout = 0;
       no_input_count = 0;