Add basic README

README.md

+# Circe PHP client lib
+
+## Dependencies
+
+PHP 7 with curl and json extensions.
+
+## Usage
+
+    <?php
+    declare(strict_types=1);
+    include "vendor/autoload.php";
+    use Certic\Circe\Client as CirceClient;
+
+    $client = new CirceClient(
+        'http://acme.tld',
+        'dont_tell_anyone',
+        'app_id');
+    $job = $client->newJob();
+    $job->addTransformation("html2pdf");
+    $job->addFile("/home/someone/example.html");
+    $client->send($job, true); // wait=true for synchronous execution
+
+    foreach ($job->getResult()->getFiles() as $file){
+        if($file->getFileName() == "out.log"){
+            echo file_get_contents((string)$file).PHP_EOL;
+        }else{
+            echo $file.PHP_EOL;
+        }
+    }
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