Gradle: Use plugins DSL where possible

apps/i2psnark/build.gradle

@@ -1,4 +1,6 @@
-apply plugin: 'war'
+plugins {
+    id 'war'
+}
 
 sourceSets {
     main {

apps/i2ptunnel/build.gradle

@@ -1,4 +1,6 @@
-apply plugin: 'war'
+plugins {
+    id 'war'
+}
 
 sourceSets {
     main {

apps/ministreaming/build.gradle

@@ -1,4 +1,6 @@
-apply plugin: 'java-library'
+plugins {
+    id 'java-library'
+}
 
 archivesBaseName = 'mstreaming'
 

apps/routerconsole/build.gradle

@@ -1,5 +1,7 @@
-apply plugin: 'war'
+plugins {
-apply plugin: 'scala'
+    id 'war'
+    id 'scala'
+}
 
 sourceSets {
     main {

apps/streaming/build.gradle

@@ -1,4 +1,6 @@
-apply plugin: 'java-library'
+plugins {
+    id 'java-library'
+}
 
 sourceSets {
     main {

apps/susidns/build.gradle

@@ -1,4 +1,6 @@
-apply plugin: 'war'
+plugins {
+    id 'war'
+}
 
 sourceSets {
     main {

apps/susimail/build.gradle

@@ -1,4 +1,6 @@
-apply plugin: 'war'
+plugins {
+    id 'war'
+}
 
 sourceSets {
     main {

build.gradle

@@ -1,4 +1,6 @@
-apply plugin: 'idea'
+plugins {
+    id 'idea'
+}
 
 // Exclude apps/ dir itself, but include its subdirs
 def javaProjects = subprojects - project(':apps')

core/build.gradle

@@ -1,5 +1,7 @@
-apply plugin: 'java-library'
+plugins {
-apply plugin: 'scala'
+    id 'java-library'
+    id 'scala'
+}
 
 archivesBaseName = 'i2p'
 

router/build.gradle

@@ -1,4 +1,6 @@
-apply plugin: 'java-library'
+plugins {
+    id 'java-library'
+}
 
 sourceSets {
     main {