Make i3bar get its config from i3 via IPC

In order to not duplicate configuration options and make stuff confusing, we
dropped the commandline flags (except for socket_path and bar_id). This means
that you *have to* specify bar_id when starting i3bar. The best way is to let
i3 start i3bar, which it will do automatically for every bar {} configuration
block it finds.

i3bar/include/config.h

@@ -13,10 +13,25 @@ typedef struct config_t {
     int          hide_on_modifier;
     dockpos_t    dockpos;
     int          verbose;
-    xcb_colors_t *colors;
+    struct xcb_color_strings_t colors;
     int          disable_ws;
+    char         *bar_id;
+    char         *command;
+    char         *fontname;
 } config_t;
 
 config_t config;
 
+/**
+ * Start parsing the received bar configuration json-string
+ *
+ */
+void parse_config_json(char *json);
+
+/**
+ * free()s the color strings as soon as they are not needed anymore.
+ *
+ */
+void free_colors(struct xcb_color_strings_t *colors);
+
 #endif

i3bar/include/xcb.h

@@ -40,10 +40,18 @@ struct xcb_color_strings_t {
 typedef struct xcb_colors_t xcb_colors_t;
 
 /*
- * Initialize xcb and use the specified fontname for text-rendering
+ * Early initialization of the connection to X11: Everything which does not
+ * depend on 'config'.
  *
  */
-char *init_xcb(char *fontname);
+char *init_xcb_early();
+
+/**
+ * Initialization which depends on 'config' being usable. Called after the
+ * configuration has arrived.
+ *
+ */
+void init_xcb_late(char *fontname);
 
 /*
  * Initialize the colors