Forwarding subprocess's stdout to logger

Using subprocess.Popen(), the output of the process is written to
logger line by line.

TODO: Currently the tab and newline character are displayed grossly
in syslog. Not sure where is the issue.

Signed-off-by: Shashank Sahni <shredder12@gmail.com>
Renamed StreamIO subclass to LogStream

Renamed StreamIO subclass to LogStream and created a new method
add_logger() to identify the logger to be used.

Unable to use current_app.logger due to app_context issues.

Signed-off-by: Shashank Sahni <shredder12@gmail.com>
Updated Remote.{run,sudo} to send output to logger

Remote.__init__() creates new LogStream object.

Remote.run/sudo() redirect stdout and stderr to LogStream.
Not sure if latter is necessary, since according to fabric docs,
they are send combined by default.

http://docs.fabfile.org/en/1.8/usage/interactivity.html#combining-stdout-and-stderr

Signed-off-by: Shashank Sahni <shredder12@gmail.com>
Changed print statements to logger.log

Signed-off-by: Shashank Sahni <shredder12@gmail.com>