bugfix: support HEAD method on Rack
Content-Length header need not delete
Merge pull request #28 from gunjisatoshi/hotfix-rack-head-method

bugfix: support HEAD method on Rack
Use 'cgi' instead of 'cgi/util' GitHub: #28

Because we don't support Ruby1.8.
Ruby1.9 or later have 'cgi/util', it defines CGI.rfc1123_date.
SImpify
use utf8 in attach_src
use utf-8 in mail
Merge pull request #30 from znz/use-utf-8-in-mail

use utf-8 in mail
Merge pull request #29 from znz/fix-encoding-in-attach_src

use utf8 in attach_src
show more user info in updating mail
Merge pull request #31 from znz/show-more-info-in-mail

show more user info in updating mail