Add functions to free objects

Introduce `pushover_free_ctx` and `pushover_free_message`.
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

libpushover/libpushover.c

@@ -57,6 +57,23 @@ out:
 	return (res);
 }
 
+EXPORTED_SYM
+void
+pushover_free_ctx(pushover_ctx_t **ctx)
+{
+	pushover_ctx_t *ctxp;
+
+	if (ctx == NULL || *ctx == NULL)
+		return;
+
+	ctxp = *ctx;
+
+	free(ctxp->psh_uri);
+	free(ctxp->psh_token);
+	free(ctxp);
+	*ctx = NULL;
+}
+
 EXPORTED_SYM
 bool
 pushover_set_uri(pushover_ctx_t *ctx, const char *uri)

libpushover/libpushover.h

@@ -34,6 +34,7 @@ typedef struct _pushover_message {
 } pushover_message_t;
 
 pushover_ctx_t *pushover_init_ctx(const char *);
+void pushover_free_ctx(pushover_ctx_t **);
 bool pushover_set_uri(pushover_ctx_t *, const char *);
 bool pushover_set_token(pushover_ctx_t *, const char *);
 pushover_message_t *pushover_init_message(pushover_message_t *);