add JMH

Add benchmark for a comparison of the custom made removeAll
method vs an implementation that uses removeIf

build.gradle

@@ -1,3 +1,16 @@
+
+buildscript {
+  repositories {
+    maven {
+      url "https://plugins.gradle.org/m2/"
+    }
+  }
+  dependencies {
+    classpath "me.champeau.gradle:jmh-gradle-plugin:0.4.5"
+  }
+}
+
+
 apply plugin: 'java'
 apply plugin: 'eclipse'
 
@@ -9,6 +22,7 @@ subprojects {
 	apply plugin: 'eclipse'
 	apply plugin: 'maven'
 	apply plugin: 'maven-publish'
+	apply plugin: 'me.champeau.gradle.jmh'
 
 	// java compatibility version
 	sourceCompatibility = 1.8
@@ -49,6 +63,10 @@ subprojects {
 	dependencies {
 		testCompile group: 'junit', name: 'junit', version: '4.12'
 	}
+	
+	jmh {
+		jvmArgsAppend = "-ea"
+	}
 }
 
 task wrapper(type: Wrapper) {