added transitive dependencies for cascading-hadoop

I needed to change build.gradle to resolve this build error:

    bash-3.2$ java -version
    java version "1.7.0_11"
    Java(TM) SE Runtime Environment (build 1.7.0_11-b21)
    Java HotSpot(TM) 64-Bit Server VM (build 23.6-b04, mixed mode)
    bash-3.2$ brew ls --versions |grep hadoop
    hadoop 1.1.1 hdfs
    bash-3.2$ gradle -version
    
    ------------------------------------------------------------
    Gradle 1.4
    ------------------------------------------------------------
    
    Gradle build time: Monday, January 28, 2013 3:42:46 AM UTC
    Groovy: 1.8.6
    Ant: Apache Ant(TM) version 1.8.4 compiled on May 22 2012
    Ivy: 2.2.0
    JVM: 1.7.0_11 (Oracle Corporation 23.6-b04)
    OS: Mac OS X 10.8.2 x86_64
    
    bash-3.2$ gradle clean jar
    :clean UP-TO-DATE
    :compileJava 
    /Users/royseto/code/CoPA/src/main/java/copa/Main.java:60: error: cannot access JobConf
        Tap gisTap = new Hfs( new TextLine( new Fields( "line" ) ), gisPath );
                            ^
      class file for org.apache.hadoop.mapred.JobConf not found
    1 error
    :compileJava FAILED
    
    FAILURE: Build failed with an exception.
    
    * What went wrong:
    Execution failed for task ':compileJava'.
    > Compilation failed; see the compiler error output for details.
    
    * Try:
    Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
    
    BUILD FAILED
    
    Total time: 6.555 secs