Add 'save' command to save preferences

Most applications have an 'apply changes' button. This makes testing
easier too.

Implement https://github.com/profanity-im/profanity/issues/1164

src/command/cmd_defs.c

@@ -2393,6 +2393,19 @@ static struct cmd_t command_defs[] =
             "/omemo untrust buddy@buddychat.org c4f9c875-144d7a3b-0c4a05b6-ca3be51a-a037f329-0bd3ae62-07f99719-55559d2a",
             "/omemo char *")
     },
+
+    { "/save",
+        parse_args, 0, 0, NULL,
+        CMD_NOSUBFUNCS
+        CMD_MAINFUNC(cmd_save)
+        CMD_NOTAGS
+        CMD_SYN(
+            "/save")
+        CMD_DESC(
+            "Save preferences to configuration file.")
+        CMD_NOARGS
+        CMD_NOEXAMPLES
+    },
 };
 
 static GHashTable *search_index;

src/command/cmd_defs.h

@@ -2,6 +2,7 @@
  * cmd_defs.h
  *
  * Copyright (C) 2012 - 2019 James Booth <boothj5@gmail.com>
+ * Copyright (C) 2019 Michael Vetter <jubalh@iodoru.org>
  *
  * This file is part of Profanity.
  *

src/command/cmd_funcs.c

@@ -2,6 +2,7 @@
  * cmd_funcs.c
  *
  * Copyright (C) 2012 - 2019 James Booth <boothj5@gmail.com>
+ * Copyright (C) 2019 Michael Vetter <jubalh@iodoru.org>
  *
  * This file is part of Profanity.
  *
@@ -8535,3 +8536,12 @@ cmd_omemo_policy(ProfWin *window, const char *const command, gchar **args)
     return TRUE;
 #endif
 }
+
+gboolean
+cmd_save(ProfWin *window, const char *const command, gchar **args)
+{
+    log_info("Saving preferences to configuration file");
+    cons_show("Saving preferences.");
+    prefs_save();
+    return TRUE;
+}

src/command/cmd_funcs.h

@@ -2,6 +2,7 @@
  * cmd_funcs.h
  *
  * Copyright (C) 2012 - 2019 James Booth <boothj5@gmail.com>
+ * Copyright (C) 2019 Michael Vetter <jubalh@iodoru.org>
  *
  * This file is part of Profanity.
  *
@@ -225,4 +226,5 @@ gboolean cmd_omemo_untrust(ProfWin *window, const char *const command, gchar **a
 gboolean cmd_omemo_policy(ProfWin *window, const char *const command, gchar **args);
 gboolean cmd_omemo_clear_device_list(ProfWin *window, const char *const command, gchar **args);
 
+gboolean cmd_save(ProfWin *window, const char *const command, gchar **args);
 #endif