Issue #800434 by pillarsdotnet, plach, bart.hanssens: Added drupal_mail(), allow hook_mail_alter() implementation to cancel mail.

Issue #1130198 by pillarsdotnet, Damien Tournoud: Fixed Regression: line-breaks are mangled by drupal_html_to_text().

#679890 follow-up by Bojhan, aspilicious, and agentrickard: Remove more extraneous 'Please' in the interface.

#497118 by chx, catch, pwolanin, JoshuaRogers, and Jacob Singh: Remove the function registry. While the hope was that this would result in improved performance for low-end hosts, it comes at the expense of critical development experience problems and less benefit than something like APC. Class registry remains intact to facilitate autoloading.

Of all the patches to accidentally commit without a message. :( Rolling back registry rip. Let's try that again.

- Patch #330084 by c960657: don't set Reply-To header unless necessary and fixed documentation issue.

  et al.  Can you say 'registry'?  Drupal now maintains an internal registry of
  all functions or classes in the system, allowing it to lazy-load code files as
  needed (reducing the amount of code that must be parsed on each request). The
  list of included files is cached per menu callback for subsequent loading by
  the menu router. This way, a given page request will have all the code it needs
  but little else, minimizing time spent parsing unneeded code.

- Patch #245115 by kkaefer, John Morahan, JohnAlbin et al: after a long discussion we've decided to make the concatenation operator consistent with the other operators.

- Patch #234403 by alienbrain: drupal_mail_send() should use CRLFs instead of LFs in e-mail headers.

#212126 report by salvis, patch by myself: allow clearing of drupal_html_to_text() URL list, so it can be used multiple times on the page

#82499 by Jose A Reyero and a little bit from myself: send emails localized in the language needed in specific situations, and centralize mail composing operations with hook_mail()

#154218 by Steven: HTML to text email converter, centralizing email wrapping in Drupal core and providing a solid conversion function for contributed modules