wicket 2.0 migrated to slf4j

[Igor Vaynberg]

i have just migrated wicket 2.0 from commons-logging to slf4j as was
previously discussed and agreed upon.

people using 2.0 need to add the following to their project's pom or
equivalent:

if you are using commons-logging:

<dependency>
     <groupId>org.slf4j</groupId>
     <artifactId>slf4j-jcl</artifactId>
    <version>1.1.0</version>
</dependency>


if you are using log4j

<dependency>
           <groupId>org.slf4j</groupId>
           <artifactId>slf4j-log4j12</artifactId>
           <version>1.1.0</version>
</dependency>

these jars will bind slf4j to the proper logging library

if you are using another logging impl like jdk see slf4j website for the
appropriate binding jar

-igor