add a few more methods methods to hadoop-compat
Merge branch 'master' into update_hadoop_compat

Conflicts:
	hadoop-compat/src/main/java/com/twitter/elephantbird/util/HadoopCompat.java
remove isFileClosed() method. Not all hadoop2 versions support this yet.
Merge pull request #368 from rangadi/update_hadoop_compat

add a few more methods methods to hadoop-compat