Fix for incorrect escaping of parameters on Windows

fixes #863 - exception when running lein check

The issues regarding the escaping of `>`, `<`, `^`, `|`, `&`, etc with `^`'s don't apply inside double-quoted strings.  All we need inside a double-quoted string is to escape `"` by doubling them, ie: `""`.

This patch assumes that `form` isn't a string literal, eg `"hello"`, else we'd end up with extra quotes, but I think that is a safe assumption - nobody will need to eval a string literal.