Add ability to test build without signing and add build instructions to the README.md

See https://stackoverflow.com/a/14869692/7518605

Use

  mvn -DperformRelease=true ...

if you need to sign your build

Author: Mingun

README.md

@@ -13,3 +13,23 @@ Further reading:
 * [About Kaitai Struct](http://kaitai.io/)
 * [About API implemented in this library](http://doc.kaitai.io/stream_api.html)
 * [Java-specific notes](http://doc.kaitai.io/lang_java.html)
+
+# Build
+To build library run the following command:
+
+```console
+mvn install
+```
+
+# Release
+To make a release ensure that you have:
+
+- a [gpg](https://gnupg.org/) installed
+- a [configured](https://maven.apache.org/plugins/maven-gpg-plugin/usage.html) gpg signing key
+- pass `-DperformRelease=true` argument to the maven command invocation:
+
+  ```console
+  mvn -DperformRelease=true deploy
+  ```
+
+See also http://doc.kaitai.io/developers.html#java.

pom.xml

@@ -54,6 +54,33 @@
         <maven.compiler.release>7</maven.compiler.release>
       </properties>
     </profile>
+    <profile>
+      <id>release-sign-artifacts</id>
+      <activation>
+        <property>
+          <name>performRelease</name>
+          <value>true</value>
+        </property>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.apache.maven.plugins</groupId>
+            <artifactId>maven-gpg-plugin</artifactId>
+            <version>3.0.1</version>
+            <executions>
+              <execution>
+                <id>sign-artifacts</id>
+                <phase>verify</phase>
+                <goals>
+                  <goal>sign</goal>
+                </goals>
+              </execution>
+            </executions>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
   </profiles>
 
   <build>
@@ -116,20 +143,6 @@
           </tags>
         </configuration>
       </plugin>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-gpg-plugin</artifactId>
-        <version>3.0.1</version>
-        <executions>
-          <execution>
-            <id>sign-artifacts</id>
-            <phase>verify</phase>
-            <goals>
-              <goal>sign</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
     </plugins>
   </build>