Start the overarching library code, and move result enum elsewhere.

src/libabacus.c

@@ -0,0 +1,11 @@
+#include "libabacus.h"
+
+libab_result libab_init(libab* ab) {
+    libab_table_init(&ab->table);
+    return libab_lexer_init(&ab->lexer);
+}
+
+libab_result libab_free(libab* ab) {
+    libab_table_free(&ab->table);
+    return libab_lexer_free(&ab->lexer);
+}