Finish Chapter 14

Implements code chunks, a couple of basic opcodes, constants, and
basic execution of those opcodes.

Signed-off-by: Daniel Henry <iamdanhenry@gmail.com>

include/value.h

@@ -0,0 +1,19 @@
+#ifndef clox_value_h
+#define clox_value_h
+
+#include "common.h"
+
+typedef double Value;
+
+typedef struct {
+  int capacity;
+  int count;
+  Value *values;
+} ValueArray;
+
+void initValueArray(ValueArray *array);
+void writeValueArray(ValueArray *array, Value value);
+void freeValueArray(ValueArray *array);
+void printValue(Value value);
+
+#endif /* clox_value_h */