Move verbosity/quiet flags from `**kwargs` to instance vars.
Move verbosity/quiet flags from `**kwargs` to instance vars.

Unfortunately, this is a breaking change for people who use these
keywords.  Nevertheless, the proliferation of **kwargs in the method
signatures is a bad smell.  The code is not self documenting.  It is not
clear from the code what keywords you can pass, and it will accept
keywords it does not use.  Also, as new methods are added, their
signatures must be polluted either by the vague `**kwargs` or a host of
seemingly irrelevant keywords, like capture_output and quiet_stderr.

Moving the verbosity and quietness functions to instance variables from
function parameters makes their functionality more well documented,
simplifies and makes more explicit  many method signatures, and
maintains the desired functionality.

For a "loud" instance, use vagrant.Vagrant(quiet_stdout=False).  Set
quiet_stderr=False for an even louder version.

In keeping with past behavior, vagrant instances are quiet by default.

todddeluca/python-vagrant,todddeluca/python-vagrant