Added possibility to export the calendar in iCal format (closes #141)

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "c1bc4c17739e9d0ee8b33628f6d4b9a4",
+    "content-hash": "0b203f875499dfeaa61890cdec018a2d",
     "packages": [
         {
             "name": "container-interop/container-interop",
@@ -104,6 +104,57 @@
             ],
             "time": "2018-01-09T20:05:19+00:00"
         },
+        {
+            "name": "eluceo/ical",
+            "version": "0.15.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/markuspoerschke/iCal.git",
+                "reference": "add0ca99aa1f77f134a2e8b071f2ebc22b115139"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/markuspoerschke/iCal/zipball/add0ca99aa1f77f134a2e8b071f2ebc22b115139",
+                "reference": "add0ca99aa1f77f134a2e8b071f2ebc22b115139",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^6.0"
+            },
+            "suggest": {
+                "ext-mbstring": "Massive performance enhancement of line folding"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Eluceo\\iCal\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Markus Poerschke",
+                    "email": "markus@eluceo.de",
+                    "role": "Developer"
+                }
+            ],
+            "description": "The eluceo/iCal package offers a abstraction layer for creating iCalendars. You can easily create iCal files by using PHP object instead of typing your *.ics file by hand. The output will follow RFC 5545 as best as possible.",
+            "homepage": "https://github.com/markuspoerschke/iCal",
+            "keywords": [
+                "calendar",
+                "iCalendar",
+                "ical",
+                "ics",
+                "php calendar"
+            ],
+            "time": "2019-01-13T22:00:58+00:00"
+        },
         {
             "name": "http-interop/http-factory",
             "version": "0.3.0",