Make the day heading position configurable

The date at the top of the appointments list may be positioned either to
the left, in the middle or to the right. Default is to the right. Can be
configured from the general options menu.

Signed-off-by: Lars Henriksen <LarsHenriksen@get2net.dk>
Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

src/calcurse.h

@@ -249,6 +249,12 @@ enum win {
 	NBWINS
 };
 
+enum pos {
+	LEFT,
+	CENTER,
+	RIGHT
+};
+
 /* General configuration variables. */
 struct conf {
 	unsigned auto_save;
@@ -265,6 +271,7 @@ struct conf {
 	const char *mergetool;
 	char output_datefmt[BUFSIZ];	/* format for displaying date */
 	int input_datefmt;	/* format for reading date */
+	enum pos heading_pos; /* left/center/right for heading in appts panel */
 	char day_heading[BUFSIZ];	/* format for displaying heading in appts panel */
 };