Merge pull request #372 from pwendell/log4j-fix-1

Send logs to stderr by default (instead of stdout).

conf/log4j.properties.template

 # Set everything to be logged to the console
 log4j.rootCategory=INFO, console
 log4j.appender.console=org.apache.log4j.ConsoleAppender
+log4j.appender.console.target=System.err
 log4j.appender.console.layout=org.apache.log4j.PatternLayout
 log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss} %p %c{1}: %m%n
 

core/src/main/resources/org/apache/spark/log4j-defaults.properties

 # Set everything to be logged to the console
 log4j.rootCategory=INFO, console
 log4j.appender.console=org.apache.log4j.ConsoleAppender
+log4j.appender.console.target=System.err
 log4j.appender.console.layout=org.apache.log4j.PatternLayout
 log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss} %p %c{1}: %m%n