added support for list directory & refined Python packaging

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#	new file:   .gitignore
#	modified:   setup.py
#	modified:   webhdfs/webhdfs.py
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#	webhdfs/__init__.pyc
#	webhdfs/webhdfs.pyc
