switch to gradle

gradle files added
gradle: plugins added
build: files added
.travis.yml: gradle cache stored
distribution: tar and zip file stuff added
broker/build.gradle: osgi plugin added
build: bintray upload added
pom: files removed
distribution: assembly.xml removed
gradle: test ouput added to sub builds
.editorconfig: gradle files added
build: wrapper task added
osgi: added to h2_ and mapdb_storage
gradle: files cleaned
build.gradle: jars used for tar/zip

distribution/src/main/assembly/assembly.xml

@@ -1,57 +0,0 @@
-<assembly xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2"
-          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-          xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.2 http://maven.apache.org/xsd/assembly-1.1.2.xsd">
-    <id>bundle-tar</id>
-    <formats>
-        <format>tar.gz</format>
-        <!--<format>dir</format>--> 
-    </formats>
-    <includeBaseDirectory>false</includeBaseDirectory> <!-- disable the creation of root's distribution dir in the archive -->
-	
-    <files>
-        <!-- executables scripts-->
-        <file>
-            <source>src/main/scripts/moquette.sh</source>
-            <outputDirectory>bin</outputDirectory>
-            <fileMode>0755</fileMode>
-        </file>
-
-        <file>
-            <source>src/main/scripts/moquette.bat</source>
-            <outputDirectory>bin</outputDirectory>
-        </file>
-        
-        <file>
-            <source>src/main/resources/log4j.properties</source>
-            <outputDirectory>config/</outputDirectory>
-            <destName>moquette-log.properties</destName>
-        </file>
-        
-        <file>
-            <source>src/main/resources/moquette.conf</source>
-            <outputDirectory>config/</outputDirectory>
-        </file>
-        
-        <file>
-            <source>src/main/resources/password_file.conf</source>
-            <outputDirectory>config/</outputDirectory>
-        </file>
-
-        <file>
-            <source>src/main/resources/hazelcast.xml</source>
-            <outputDirectory>config/</outputDirectory>
-        </file>
-        
-        <file>
-            <source>src/main/resources/README.txt</source>
-        </file>
-    </files>     
-    
-	
-    <dependencySets>
-        <dependencySet>
-            <outputDirectory>lib/</outputDirectory>
-            <useProjectArtifact>true</useProjectArtifact> <!-- avoid inclusion of the artifact itself --> 
-        </dependencySet>
-    </dependencySets>
-</assembly>