logic: added Gradle project setup (issue #379)

* added implementation for Gradle project setup (icon is still missing)
* refactored project loading/saving and SourceGroupSettings
* removed long deprecated Cxx UseSourcePathsForHeaderSearch option

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java_indexer/pom.xml

@@ -24,11 +24,37 @@
 		</plugins>
     </build>
 	
+	<repositories>
+		<repository>
+			<id>mvnrepository</id>
+			<name>mvnrepository</name>
+			<url>http://www.mvnrepository.com</url>
+		</repository>
+		<repository>
+			<id>repo_gradle</id>
+			<name>repo_gradle</name>
+			<url>http://repo.gradle.org/gradle/libs-releases-local</url>
+		</repository>
+	</repositories>
+	
 	<dependencies>
 		<dependency>
 			<groupId>org.eclipse.jdt</groupId>
 			<artifactId>org.eclipse.jdt.core</artifactId>
 			<version>3.12.3</version>
 		</dependency>
+		
+		<dependency>
+			<groupId>org.gradle</groupId>
+			<artifactId>gradle-tooling-api</artifactId>
+			<version>4.2</version>
+		</dependency>
+		
+		<dependency>
+			<groupId>org.slf4j</groupId>
+			<artifactId>slf4j-simple</artifactId>
+			<version>1.7.10</version>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 </project>