a: now use filter_var to test is_email, allows us to get rid of lots of code.
b: fixes to cms_admin_tabs class
c: adds the cms_mailer class which is a wrapper around phpmailer
d: moves phpmailer into lib directory.
e: removes admin interface from CMSMailer
f: reorganize siteprefs template and code
g: adds mail settings and test functionality into siteprefs
h: officialy deprecate CMSMailer.