Formatting commit :(

I know formatting commits suck... And I try to avoid them.

But this commit was absolutely necessary... The coding style in this
program was not ok and not the same over the whole program.

The commit is hard to read, but this is what I changed:
- Tabs for indentation instead of spaces
- Same style over the whole program (suckless style)

CONTRIBUTING.md

@@ -1,4 +1,4 @@
 Contributing
 ============
 
-If you want to contribute, please use [the suckless coding style](http://suckless.org/coding_style) and 4 spaces for indentation.
+If you want to contribute, please use [the suckless coding style](http://suckless.org/coding_style).

README.md

@@ -38,7 +38,7 @@ Put the following code in your ~/.xinitrc (or similar):
 
 ```
 while true; do
-    slstatus
+	slstatus
 done &
 ```
 

config.def.h

@@ -1,12 +1,12 @@
 /* See LICENSE file for copyright and license details. */
 
 /* alsa sound */
-static const char channel[]   = "Master";
+static const char channel[]         = "Master";
 
 /* battery */
-static const char batterypath[] = "/sys/class/power_supply/";
-static const char batterynow[]  = "energy_now";
-static const char batteryfull[] = "energy_full_design";
+static const char batterypath[]     = "/sys/class/power_supply/";
+static const char batterynow[]      = "energy_now";
+static const char batteryfull[]     = "energy_full_design";
 
 /* bar update interval in seconds (smallest value = 1) */
 static unsigned int update_interval = 1;
@@ -35,13 +35,13 @@ static unsigned int update_interval = 1;
 - wifi_perc (wifi signal in percent) [argument: wifi card interface name]
 - wifi_essid (wifi essid) [argument: wifi card interface name] */
 static const struct arg args[] = {
-    /* function     format          argument */
-    { wifi_perc,    "wifi %4s | ",  "wlp3s0" },
-    { battery_perc, "bat %4s | ",   "BAT0" },
-    { cpu_perc,     "cpu %4s ",     NULL },
-    { temp,         "%3s | ",       "/sys/devices/platform/coretemp.0/hwmon/hwmon2/temp1_input" },
-    { ram_perc,     "ram %3s | ",   NULL },
-    { vol_perc,     "vol %4s | ",   "default" },
-    { disk_perc,    "ssd %3s | ",   "/" },
-    { datetime,     "%s",           "%y-%m-%d %H:%M:%S" },
+	/* function     format          argument */
+	{ wifi_perc,    "wifi %4s | ",  "wlp3s0" },
+	{ battery_perc, "bat %4s | ",   "BAT0" },
+	{ cpu_perc,     "cpu %4s ",     NULL },
+	{ temp,         "%3s | ",       "/sys/devices/platform/coretemp.0/hwmon/hwmon2/temp1_input" },
+	{ ram_perc,     "ram %3s | ",   NULL },
+	{ vol_perc,     "vol %4s | ",   "default" },
+	{ disk_perc,    "ssd %3s | ",   "/" },
+	{ datetime,     "%s",           "%y-%m-%d %H:%M:%S" },
 };

slstatus.h

@@ -6,9 +6,9 @@ static Display *dpy;
 /* statusbar configuration type and struct */
 typedef char *(*op_fun) (const char *);
 struct arg {
-    op_fun func;
-    const char *format;
-    const char *args;
+	op_fun func;
+	const char *format;
+	const char *args;
 };
 
 /* functions */