added the playlist order tag, updated pom, added greek translation

+ Added the playlist order tag

Some people might find it useful to maintain the order of the downloaded songs from a playlist. For this reason I have included the <%> tag which does exactly that (and works like the <#> tag)

+ Updated pom.xml 
 
Added the maven-compiler-plugin, indicating to newer JDK versions that the source code is  written in Java 1.5 and that the compiled bytecode should adhere to Java 1.5 

+ Added the Greek language translation