Make it easier to get started with Eclipse.

This patch makes mvn eclipse:eclipse generate additional eclipse configuration
files so that Eclipse:
 - uses Java 1.6 compliance level,
 - truncates lines after 140 chars,
 - uses 4 spaces for indentation,
 - automatically adds a license header when creating a new class file,
 - organizes imports the same way as Intellij Idea (which makes sense I guess
   since most of the code bas has been written with Intellij, this will prevent
   from having large diffs due to the fact that the order of imports has
   changed).

pom.xml

@@ -883,6 +883,26 @@
                         </lifecycleMappingMetadata>
                     </configuration>
                 </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-eclipse-plugin</artifactId>
+                    <configuration>
+                        <additionalConfig>
+                            <file>
+                                <name>.settings/org.eclipse.jdt.core.prefs</name>
+                                <location>src/eclipse/dot.settings/org.eclipse.jdt.core.prefs</location>
+                            </file>
+                            <file>
+                                <name>.settings/org.eclipse.jdt.ui.prefs</name>
+                                <location>src/eclipse/dot.settings/org.eclipse.jdt.ui.prefs</location>
+                            </file>
+                            <file>
+                                <name>.settings/org.eclipse.core.resources.prefs</name>
+                                <location>src/eclipse/dot.settings/org.eclipse.core.resources.prefs</location>
+                            </file>
+                        </additionalConfig>
+                    </configuration>
+                </plugin>
             </plugins>
         </pluginManagement>
     </build>

src/eclipse/README

@@ -0,0 +1,6 @@
+Eclipse configuration files
+
+You can use them by running
+  mvn eclipse:clean eclipse:eclipse
+and importing the project into Eclipse (File > Import > Existing Project into
+workspace) or refreshing it (F5) if you already imported it.

src/eclipse/dot.settings/org.eclipse.core.resources.prefs

@@ -0,0 +1,2 @@
+eclipse.preferences.version=1
+encoding/<project>=UTF-8

src/eclipse/dot.settings/org.eclipse.jdt.core.prefs

@@ -0,0 +1,10 @@
+eclipse.preferences.version=1
+# We target Java 1.6
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.6
+org.eclipse.jdt.core.compiler.compliance=1.6
+org.eclipse.jdt.core.compiler.source=1.6
+# Lines should be splitted at 140 chars
+org.eclipse.jdt.core.formatter.lineSplit=140
+# Indentation is 4 spaces
+org.eclipse.jdt.core.formatter.tabulation.char=space
+org.eclipse.jdt.core.formatter.tabulation.size=4