search params preference for "+" over "%20"

[stevenvachon]

... since they're easier to read.

http://domain/dir name/?va r=va lue

should parse as:

http://domain/dir%20name/?va+r=va+lue

instead of:

http://domain/dir%20name/?va%20r=va%20lue

by default

[annevk]

This is a duplicate of #18. I don't disagree that it would be nice if they worked the same way, but I doubt we're going to get convergence there.