Adding installation instructions to README

This text was previously provided by Justing Clift in
a pull request. Submitting now as a gerrit review.

Change-Id: I2f2bcd894c5eb58318d85b5856366ff31e2a423e
Signed-off-by: Thiago da Silva <thiago@redhat.com>
adding new methods to Volume class

These are mostly helper methods similar to functions provided
by the python os module
helpfer functions added: exists, getsize, isdir, isfile, islink
glfs functions added: removexattr, stat

Change-Id: I3581a96224151481292a4e506d8c52b8acf79e49
Signed-off-by: Thiago da Silva <thiago@redhat.com>
added Apache license comment to source code

Added same license as gluster-swift

Change-Id: Ib190b4e6def5d2ab87b71a04142f6344060d8a6d
Signed-off-by: Thiago da Silva <thiago@redhat.com>