Copy examples from example repo

Fixes #4

examples/.gitignore

@@ -0,0 +1,4 @@
+!/*.php
+/*.xml
+/composer.lock
+/vendor/

examples/composer.json

@@ -0,0 +1,8 @@
+{
+    "require": {
+        "opdavies/gmail-filter-builder": "^1.1"
+    },
+    "scripts": {
+        "generate": "generate-filters"
+    }
+}

examples/filters.php

@@ -0,0 +1,15 @@
+<?php
+
+use Opdavies\GmailFilterBuilder\Filter;
+
+require_once __DIR__ . '/vendor/autoload.php';
+
+return [
+    Filter::create()
+        ->from('foo@example.com')
+        ->labelAndArchive('Example'),
+
+    Filter::create()
+        ->from('bar@example.com')
+        ->important(),
+];