new test file test/test_mechanize_page_image.rb
new methods: Page#image(s)_with, Image#alt(and major attrs), Image#caption, Image#pretty_print

  agent.page.image_with(:alt => 'alt-string')
  agent.page.image_with(:title => 'image title')

Image#caption returns "ALT" when <img alt="ALT">
Image#caption returns "TITLE" when <img title="TITLE">
Image#caption returns "TITLE" when <img alt="ALT" title="TITLE">
Image#caption returns "" when <img> (no alt nor title)

  p page.images[0] #=> #<Mechanize::Page::Image "src-url" "caption">
new methods: Image#extname(alias #suffix), Image#mime_type

Image#extname (alias Image#suffix) returns image url suffix.
  p page.images[0].url #=> "http://example/test.jpg"
  p page.images[0].extname #=> ".jpg"
dot is not 'delimiter' but part of suffix.

Image#mime_type returns mime type of image url.
  p page.images[0].extname #=> ".jpg"
  p page.images[0].mime_type #=> "image/jpeg"
Note that they do not come from real server responses.
new methods: Image#fetch, Image#save, Image#download

Page::Image#fetch gets self like Link#click. The referer is usually the agent.page.

  agent.get('http://www.ruby-lang.org/en/')
  agent.page.image_with(:src => /logo/).fetch
  p agent.page.uri.to_s #=> "http://www.ruby-lang.org/images/logo.gif"

Image#save fetches image and #save.

Image#download saves image without adding to history.
Fix charset name extraction.  Issue #180
Added attr_accessor :filename to Mechanize::Download

Mechanize::Download calls extract_filename in it's initialize method
but filename doesn't accessible.
Do not include user information or fragment part from a Referer URI.

It is required by RFC 2616 14.36 that a Referer URI MUST NOT include a
fragment part.

As for the user information part there seems to be no explicit mention
in RFC 2616 nor RFC 3986, but I believe we should just follow what
most major browsers do and remove user information part if any for
security reasons.
Add back broken charset support.  Make charset_from_content_type an alias for charset.
Implement the alt-text of XKCD 903
Work around disambiguation pages like "Free association"
Subtract one from count to ignore first-page search or random
Updated list of supported Ruby versions in the README.
Use net-http-persistent 2.4 with the SSL proxy fix
Use a nonexistent file in a temporary directory since /nonexistent sometimes exists on travis
Merge pull request #190 from steveklabnik/patch-1

Updated list of supported Ruby versions in the README.
Merge pull request #184 from yury/download_filename

Added attr_accessor :filename to Mechanize::Download
Unlink tempfiles at creation to avoid finalizer issues.  Issue #183
Set the default maximum history size to 50 pages (from unlimited) to allow tempfiles to be purged sooner.  Related to Issue #183
Switch to always manually copying the file from the tempfile since it is unlinked.  Fix download save test to run the block.

Possibly fixes Issue #188
Ruby 1.8.7 does not allow calling Tempfile#close! twice