Fixes for a bunch of compiler warnings.

ui.c

@@ -177,7 +177,7 @@ static void draw_bar_scale(int* y) {
 
 void draw_line_total(float sent, float recv, int y, int x, option_linedisplay_t linedisplay, int bytes) {
     char buf[10];
-    float n;
+    float n = 0;
     switch(linedisplay) {
         case OPTION_LINEDISPLAY_TWO_LINE:
           draw_line_total(sent, recv, y, x, OPTION_LINEDISPLAY_ONE_LINE_SENT, bytes);