chore: remove unused hashtable and dead code

Remove hashtable module and tests (unused in runtime). Remove unused
variables mycolour, direction, output_scale_factor, and dead local p.

include/hashtable.h

@@ -1,116 +0,0 @@
-#ifndef HASHTABLE_H
-#define HASHTABLE_H
-
-#include <stdbool.h>
-
-struct htobj;
-typedef struct htobj *hashtable;
-
-typedef struct {
-	struct htobj *h;
-	struct entry *entry;
-	int index;
-} ht_iterator;
-
-/**
- * @brief Create a new hashtable
- *
- * This function creates a new hashtable with the specified size.
- * It initializes the table with NULL entries.
- *
- * @param size The size of the hashtable
- * @return A pointer to the newly created hashtable
- */
-hashtable hashtable_new(int size);
-
-/**
- * @brief Insert a new key-value pair into the hashtable
- *
- * This function inserts a new key-value pair into the hashtable.
- * It calculates the index using the hash function and inserts the
- * key-value pair at the beginning of the linked list at that index.
- *
- * @param h Pointer to the hashtable
- * @param key Pointer to the key
- * @param value Pointer to the value
- * @return null or pointer to the previous value of the key
- */
-void *hashtable_set(hashtable h, const char *key, void *value);
-
-/**
- * @brief Get the value associated with a key from the hashtable
- *
- * This function takes a hashtable and a key as input and returns the
- * value associated with the key. If the key is not found in the
- * hashtable, it returns NULL.
- *
- * @param h Pointer to the hashtable
- * @param key Pointer to the key
- * @return Pointer to the value associated with the key, or NULL if not found
- */
-void *hashtable_lookup(hashtable h, const char *key);
-
-/**
- * @brief Remove a key-value pair from the hashtable
- *
- * This function removes a key-value pair from the hashtable.
- * It calculates the index using the hash function and traverses
- * the linked list at that index. If the key is found, it removes
- * the corresponding entry from the linked list and frees the memory.
- *
- * @param h Pointer to the hashtable
- * @param key Pointer to the key to remove
- * @return null or value associated with the removed key.
- */
-void *hashtable_remove(hashtable h, const char *key);
-
-/**
- * @brief Destroy hashtable.
- *
- * Values must be destroyed by the caller earlier.
- *
- * @param h Reference to the hastable.
- */
-void hashtable_destroy(hashtable h);
-
-/**
- * @brief Get the iterator of key-value pairs in the hashtable
- *
- * This function returns the iterator of key-value pairs in the hashtable.
- *
- * @param h Pointer to the hashtable
- * @return The iterator of key-value pairs in the hashtable
- */
-ht_iterator hashtable_iter(hashtable h);
-
-/**
- * @brief Get the next key-value pair from the iterator
- *
- * This function returns the next key-value pair from the iterator.
- *
- * @param iter Pointer to the iterator
- * @return true if there is a next key-value pair, false otherwise
- */
-bool ht_iter_next(ht_iterator *iter);
-
-/**
- * @brief Get the key from the iterator
- *
- * This function returns the key from the iterator.
- *
- * @param iter Pointer to the iterator
- * @return The key from the iterator
- */
-const char *ht_iter_key(ht_iterator *iter);
-
-/**
- * @brief Get the value from the iterator
- *
- * This function returns the value from the iterator.
- *
- * @param iter Pointer to the iterator
- * @return The value from the iterator
- */
-void *ht_iter_value(ht_iterator *iter);
-
-#endif