update readme & fix pom warnings

Author: JasperGeurtz

README.md

@@ -18,4 +18,8 @@ Have a similar (java) interface to BWMirror to make porting bwmirror bots easy w
  - fast (citation needed)
 
 ### compilation
+`mvnw.cmd package`
+
+or if you already have maven installed
+
 `mvn package`

pom.xml

@@ -7,11 +7,17 @@
     <groupId>jbwapi</groupId>
     <artifactId>jbwapi</artifactId>
     <version>0.1</version>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
     <build>
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.0</version>
                 <configuration>
                     <source>8</source>
                     <target>8</target>