Updates to 3rd party libraries

Add Dockerfile and specific docker-php.ini

inc/vendor/markbaker/complex/classes/src/operations/subtract.php

@@ -0,0 +1,46 @@
+<?php
+
+/**
+ *
+ * Function code for the complex subtraction operation
+ *
+ * @copyright  Copyright (c) 2013-2018 Mark Baker (https://github.com/MarkBaker/PHPComplex)
+ * @license    https://opensource.org/licenses/MIT    MIT
+ */
+namespace Complex;
+
+/**
+ * Subtracts two or more complex numbers
+ *
+ * @param     array of string|integer|float|Complex    $complexValues   The numbers to subtract
+ * @return    Complex
+ */
+function subtract(...$complexValues)
+{
+    if (count($complexValues) < 2) {
+        throw new \Exception('This function requires at least 2 arguments');
+    }
+
+    $base = array_shift($complexValues);
+    $result = clone Complex::validateComplexArgument($base);
+
+    foreach ($complexValues as $complex) {
+        $complex = Complex::validateComplexArgument($complex);
+
+        if ($result->isComplex() && $complex->isComplex() &&
+            $result->getSuffix() !== $complex->getSuffix()) {
+            throw new Exception('Suffix Mismatch');
+        }
+
+        $real = $result->getReal() - $complex->getReal();
+        $imaginary = $result->getImaginary() - $complex->getImaginary();
+
+        $result = new Complex(
+            $real,
+            $imaginary,
+            ($imaginary == 0.0) ? null : max($result->getSuffix(), $complex->getSuffix())
+        );
+    }
+
+    return $result;
+}