Configure Gradle build

- Set version at 0.1.0-SNAPSHOT, per http://semver.org practices
 - Configure dependencies per existing Maven pom
 - Resolve dependencies from jcenter by default, mavenLocal for custom
   BitcoinJ and TomP2P binaries (which still must be built separately)
 - Copy non-java files (fxml, etc) from src/main/java when processing
   resources

`./gradle build` is now completes successfully.

build.gradle

@@ -1,2 +1,32 @@
+apply plugin: 'java'
+
+version = '0.1.0-SNAPSHOT'
+sourceCompatibility = 1.8
+
+sourceSets.main.resources.srcDirs += 'src/main/java'
+
+repositories {
+    jcenter()
+    mavenLocal()
+}
+
+dependencies {
+    compile 'com.google:bitcoinj:0.12-SNAPSHOT'
+    compile 'net.tomp2p:tomp2p-all:5.0-Alpha24-SNAPSHOT'
+    compile 'org.slf4j:slf4j-api:1.7.7'
+    compile 'ch.qos.logback:logback-core:1.1.2'
+    compile 'ch.qos.logback:logback-classic:1.1.2'
+    compile 'com.google.inject:guice:3.0'
+    compile 'com.google.guava:guava:16.0.1'
+    compile 'com.google.code.gson:gson:2.2.4'
+    compile 'org.controlsfx:controlsfx:8.0.5'
+    compile 'de.jensd:fontawesomefx:8.0.0'
+    compile 'net.glxn:qrgen:1.3'
+    compile 'com.google.code.findbugs:jsr305:2.0.3'
+    compile 'net.jcip:jcip-annotations:1.0'
+    compile 'org.jetbrains:annotations:13.0'
+    testCompile 'junit:junit:4.11'
+    testCompile 'org.mockito:mockito-all:1.9.5'
+}
 
 wrapper.gradleVersion = '2.0'