First version of #25 implementation, providing memory_get_usage/memory_get_peak_usage/memory_limit

tests/memory_usage.aer

@@ -0,0 +1,19 @@
+class Main {
+
+	public function __construct() {
+		$this->displayMem();
+	}
+
+	private function displayMem() {
+		$bytes = memory_get_usage();
+		$peak = memory_get_peak_usage();
+		$limit = memory_limit();
+		var_export($bytes > 0);
+		var_export($peak > 0);
+		var_export($peak >= $bytes);
+		var_export($limit == 0 || $limit > $bytes);
+	}
+
+}
+
+new Main();