Add phpcs.xml (#15)

simplepie#879

.editorconfig

@@ -26,3 +26,6 @@ indent_style = space
 [*.{yaml,yml}]
 indent_size = 2
 indent_style = space
+
+[*.xml]
+indent_style = tab

phpcs.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ruleset name="SimplePie">
+	<arg name="extensions" value="php"/>
+	<exclude-pattern>./.git/</exclude-pattern>
+	<exclude-pattern>./compatibility_test/</exclude-pattern>
+	<exclude-pattern>./vendor/</exclude-pattern>
+	<rule ref="PSR12">
+		<exclude name="PSR1.Files.SideEffects.FoundWithSymbols"/>
+		<exclude name="PSR1.Methods.CamelCapsMethodName.NotCamelCaps"/>
+		<exclude name="PSR12.ControlStructures.ControlStructureSpacing.FirstExpressionLine"/>
+		<exclude name="Squiz.ControlStructures.ControlSignature.SpaceAfterCloseBrace"/>
+	</rule>
+	<rule ref="Generic.Files.LineLength">
+		<properties>
+			<property name="lineLimit" value="165"/>
+			<property name="absoluteLineLimit" value="400"/>
+		</properties>
+	</rule>
+</ruleset>