420848 - maven-compiler-plugin source/target 1.8 not recognized

The jdt component of m2e v1.4 does not import java 1.8 projects correctly into eclipse.
Instead of setting the compiler compliance level to java 1.8, java 1.4 is used.
This patch fixes this issue by adding JavaSE-1.8 to the list of known java runtime environments
and adding java 1.8 (respectively java 8) to the list of known source/target compliance levels.

This contribution complies with http://www.eclipse.org/legal/CoO.php

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=420848
Signed-off-by: Daniel Dietrich <daniel.dietrich@gmx.net>

org.eclipse.m2e.tests/projects/compilerSettings18/pom.xml

@@ -0,0 +1,30 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" 
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>org.eclipse.m2e.test</groupId>
+    <artifactId>m2e-test-parent</artifactId>
+    <version>1.0.0</version>
+  </parent>
+
+  <groupId>org.eclipse.m2e.projects</groupId>
+  <artifactId>compilerSettings18</artifactId>
+  <version>1.0.0-SNAPSHOT</version>
+  <packaging>jar</packaging>
+  <description>test project for bug 420848</description>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <configuration>
+          <source>1.8</source>
+          <target>1.8</target>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

org.eclipse.m2e.tests/src/org/eclipse/m2e/tests/project/CompilerSettings18Test.java

@@ -0,0 +1,23 @@
+
+package org.eclipse.m2e.tests.project;
+
+import org.eclipse.core.resources.IProject;
+import org.eclipse.jdt.core.IJavaProject;
+import org.eclipse.jdt.core.JavaCore;
+
+import org.eclipse.m2e.tests.common.AbstractMavenProjectTestCase;
+
+
+public class CompilerSettings18Test extends AbstractMavenProjectTestCase {
+
+  public void testCompilerSettings18() throws Exception {
+    IProject project = importProject("projects/compilerSettings18/pom.xml");
+    assertNoErrors(project);
+    waitForJobsToComplete();
+
+    IJavaProject javaProject = JavaCore.create(project);
+    assertEquals("1.8", javaProject.getOption(JavaCore.COMPILER_SOURCE, true));
+    assertEquals("1.8", javaProject.getOption(JavaCore.COMPILER_CODEGEN_TARGET_PLATFORM, true));
+  }
+
+}