Mailer:

* added an application setting to specify the application protocol (http or https) used to generate urls
* added layouts for text and html emails
* no more language specific templates
* urls are now generated using UrlWriter
* the mailer now uses AdvAttrAccessor code style to set email parameters

git-svn-id: http://redmine.rubyforge.org/svn/trunk@877 e93f8b46-1217-0410-a6f0-8f06a7374b81