A new utility method Mechanize::Util.each_parameter is added, and Mechanize::Util.build_query_string is enhanced for this feature.
Improve documentation while at it.
- css - xpath - at_css - at_xpath - % (alias for at)
This is a workaround for a bug of URI#+ that led to failure in resolving a relative path containing double slash like "/../http://.../". GH #304