replace invoice-pdf.php with more robust pdf-php library version

.gitignore

@@ -1,4 +1,7 @@
 # ignore visual studio code configuration
 .vscode
 # ignore .svn
-.svn
+.svn
+
+# ignore composer vendor path
+vendor

.gitmodules

@@ -1,4 +1,6 @@
 [submodule "pdf-php"]
-	path = pdf-php
-	url = https://github.com/rospdf/pdf-php.git
-	branch = experimental-src
+	path = vendor/rospdf/pdf-php
+	url = https://github.com/rospdf/pdf-php
+[submodule "vendor/rospdf/pdf-php"]
+	path = vendor/rospdf/pdf-php
+	url = https://github.com/rospdf/pdf-php

composer.json

@@ -0,0 +1,18 @@
+{
+    "name": "ole1986/wc-invoice-pdf",
+    "type": "",
+    "description": "WC Recurring Invoice Pdf plugin for wordpress",
+    "homepage": "https://github.com/ole1986/wc-invoice-pdf",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Ole Koeckemann",
+            "email": "[email protected]",
+            "role": "Project Head / Developer"
+        }
+    ],
+    "require": {
+        "php": ">=5.4.0",
+        "rospdf/pdf-php": "0.12.*"
+    }
+}