Added XML output and Xpath filtering - 2nd attempt

I added the ability for the user to specify XML output using --format xml at the command line. I also added the optional use of xpath expressions in the commands file.

An example line from the commands file might look like this -

show route 2600::/64 % //rt-entry

The op command is separated from the xpath expression by a '%' character.
WIll fix doc strings and remove the re module.

On Mon, Sep 8, 2014 at 9:05 PM, Nathan Printz <notifications@github.com>
wrote:

> In jaide.py:
>
> > @@ -545,8 +549,25 @@ def make_commit(conn, ip, commands, commit_check, quiet, commit_confirm, commit_
> >      conn.close_session()
> >      return screen_output
> >
> > +def xpath_filter(router_output, xpath_expr):
>
> A function docstring would conform to the documentation convention of the
> rest of Jaide.
>
> --
> Reply to this email directly or view it on GitHub
> <https://github.com/NetworkAutomation/jaide/pull/2/files#r17277230>.
>