Update junit related PMD rules

The following rules are disabled:
 * JUnitSpelling: Checking the spelling of several junit methods is no
   longer required with junit 4 since we use annotations to mark junit
   related methods.
 * JUnitTestsShouldIncludeAssert: We use Mockito verification in many
   tests. Hence, it is okay to have tests without asserts.
 * JUnitAssertionsShouldIncludeMessage: Including a message in every
   assert appears to be too verbose.

The commit also adds the .eclipse-pmd file to gitignore. This file
holds the configuration of the eclipse-pmd plugin (an alternative to
the pmd-eclipse-plugin).

Author: cboehme

.gitignore

@@ -4,6 +4,7 @@
 # Ignore Eclipse project files:
 .checkstyle
 .pmd
+.eclipse-pmd
 .classpath
 .project
 .settings/

quality_assurance/pmd_rules.xml

@@ -50,7 +50,9 @@
 	</rule>
 	<rule ref="rulesets/java/junit.xml">
 		<exclude name="JUnitTestContainsTooManyAsserts" />
-		<exclude name="UseAssertTrueInsteadOfAssertEquals" />
+		<exclude name="JUnitSpelling" />
+		<exclude name="JUnitAssertionsShouldIncludeMessage" />
+		<exclude name="JUnitTestsShouldIncludeAssert" />
 	</rule>
 	<rule ref="rulesets/java/logging-java.xml" />
 	<rule ref="rulesets/java/migrating.xml" />