Rewrite the entire code-base

The following changes are focused upon:
- Modularity
- Doing away with globals
- No heap allocations
- Better command line interface
- Switch from Xlib to XCB
- More verbose type definitions
- Implement a single-file config by utilising X-macros

include/timer.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <signal.h>
+
+#define TIMER_SIGNAL SIGALRM
+
+typedef struct {
+    unsigned int time;
+    const unsigned int tick;
+    const unsigned int reset_value;
+} timer;
+
+timer timer_new(void);
+int timer_arm(timer *const timer);