Clean up SLF4J from shaded jar and remove startup warnings (fixes #79)

Author: karoliineh

pom.xml

@@ -84,9 +84,19 @@
                     <groupId>commons-logging</groupId>
                     <artifactId>commons-logging</artifactId>
                 </exclusion>
+                <exclusion>
+                    <groupId>org.slf4j</groupId>
+                    <artifactId>slf4j-simple</artifactId>
+                </exclusion>
             </exclusions>
         </dependency>
 
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-nop</artifactId>
+            <version>2.0.17</version>
+        </dependency>
+
         <!-- graphviz-java -->
         <dependency>
             <groupId>guru.nidi</groupId>