Add function prototypes for four basic libregex functions.

include/libregex.h

@@ -292,4 +292,30 @@ typedef struct regex_match_s regex_match;
 typedef struct regex_result_s regex_result;
 typedef struct regex_sim_s regex_sim;
 
+/**
+ * Clears a node completely, resetting all the values to default.
+ * @param node the node to clear.
+ */
+void regex_node_clear(regex_node* node);
+/**
+ * Frees an entire NFA, starting from the given root node.
+ * @param root the root, or starting node, of the NFA.
+ */
+void regex_free(regex_node* root);
+/**
+ * Builds a regular expression from the given regular expression strings.
+ * @param root the root node to build into.
+ * @param expression the expression to construct the NFA from.
+ * @return the result of the operation: LIBREGEX_SUCCESS if all goes well, or an error code.
+ */
+libregex_result regex_build(regex_node** root, char* expression);
+/**
+ * Matches the regular expression against a given string.
+ * @param root the root of a regular expression NFA
+ * @param string the string to be matched
+ * @param result the result to be populated with the data from matching the string.
+ * @return the result of the operation: LIBREGEX_SUCCESS if all goes well, or an error code.
+ */
+libregex_result regex_match_string(regex_node* root, char* string, regex_result* result);
+
 #endif