pom.xml(maven-compiler-plugin): update to 3.6.0

See https://mail-archives.apache.org/mod_mbox/maven-announce/201610.mbox/%3Cop.yp5p3mm2kdkhrr%40desktop-2khsk44.dynamic.ziggo.nl%3E

Also activate new failOnWarning option.

No functional changes.

Author: php-coder

pom.xml

@@ -368,7 +368,7 @@
 		<commons-pool.version>1.5.4</commons-pool.version>
 
 		<commons.lang.version>3.4</commons.lang.version>
-		<compiler.plugin.version>3.5.1</compiler.plugin.version>
+		<compiler.plugin.version>3.6.0</compiler.plugin.version>
 		<coveralls.plugin.version>2.2.0</coveralls.plugin.version>
 		<enforcer.plugin.version>1.4.1</enforcer.plugin.version>
 		<failsafe.plugin.version>2.19.1</failsafe.plugin.version>
@@ -630,6 +630,7 @@
 					<showDeprecation>true</showDeprecation>
 					<showWarnings>true</showWarnings>
 					<debug>false</debug>
+					<failOnWarning>true</failOnWarning>
 				</configuration>
 			</plugin>