Adds string transform for stripping whitespace
Adds string transform for stripping whitespace

I find I make this transform a lot. It would be nice to add it to the
framework

alecthomas/voluptuous,SimplyKnownAsG/voluptuous,tuukkamustonen/voluptuous,jmwri/voluptuous,tuukkamustonen/voluptuous,alecthomas/voluptuous,divanovGH/voluptuous,SimplyKnownAsG/voluptuous