Refactored a bit openerp/tools about (e)mails and html.
- moved some (e)mail related functions from misc to mail
- moved html_sanitizer into mail
- added html_email_clean, to clean incoming emails (remove quotes, signature)
- added a plaintext2html function, to convert plaintext into html (\n and \r are replaced by <br/>, more than two <br/> are replaced by end and beginning of paragraphs)
- append_content_to_html now uses plaintext2html, according to some new flags
- added tests for html_email_clean, plaintext2html, updated test for append_content_to_html, html_sanitize
bzr revid: tde@openerp.com-20121114150442-4rpfdy9spm1ig0qw