mailwrap.html is back

@EMAILSIGNATURE@ added

Additional bug fix

Done:
Cleanup of the mail text signature.
The signature is deleted from the txt files and moved in to lang.php
Mailer.class.php updated to insert the signature

Fix:
- Cleaner text
- no more "-- "  "--" "---" "----" problems.
- mailwrap.html is not needed anymore an can be deleted (?)

Changed files in all languages:
lang.php
mailtext.txt
password.txt
registermail.txt
subscr_digest.txt
subscr_list.txt
subscr_single.txt
uploadmail.txt
pwconfirm.txt
showrev.txt

delete?:
mailwrap.html

This change improves consistency with neighboring links such as "Update Profile" and "Register", which are two action verbs. "Login" and "Logout" were nouns and not verbs. Title case capitalization is applied because of "Update Profile".

To improve consistency: it is surrounded by "Update Profile" and "Media Manager".