Feature/merge smarty-phpunit into tests subfolder (#580)

* Removed unneeded files and replace dummy.txt with .gitignore files
* Synced unit tests with master codebase, noted TODO's, fixed phpunit scripts and travis config
* fix php7.4 deprecation and remove php7.4 from travis allow_failures since php7.4 is current stable

Co-authored-by: Uwe Tews <uwe.tews@googlemail.com>
Co-authored-by: Uwe Tews <uwe.tews@gmail.com>
Co-authored-by: AnrDaemon <anrdaemon@yandex.ru>

tests/UnitTests/__shared/PHPunitplugins/compiler.getparamsshort.php

@@ -0,0 +1,56 @@
+<?php
+/**
+ * Smarty plugin params
+ *
+ * @package    Smarty
+ * @subpackage PHPunitPlugin
+ */
+
+/**
+ * Smarty {getparams}
+ *
+ * @param array  $params   parameter array
+ * @param object $template template object
+ *
+ * @return string
+ */
+class smarty_compiler_getparamsshort extends Smarty_Internal_CompileBase
+{
+    /**
+     * Attribute definition: Overwrites base class.
+     *
+     * @var array
+     * @see Smarty_Internal_CompileBase
+     */
+    public $required_attributes = array();
+
+    /**
+     * Attribute definition: Overwrites base class.
+     *
+     * @var array
+     * @see Smarty_Internal_CompileBase
+     */
+    public $optional_attributes = array('_any');
+    /**
+     * Attribute definition: Overwrites base class.
+     *
+     * @var array
+     * @see Smarty_Internal_CompileBase
+     */
+    public $shorttag_order = array('s1', 's2', 's3');
+
+    public function compile($args, $compiler)
+    {
+        $_attr = $this->getAttributes($compiler, $args);
+        $output = '<?php echo "array(';
+             foreach ($_attr as $key => $value) {
+                $output .= "'{$key}'=>\" . ";
+                $output .= is_string($value) ? "({$value})" : ("'" . var_export($value, true). "'");
+                $output .= ' . ",';
+
+            }
+
+        $output .= ")\";?>\n";
+        return $output;
+    }
+}