also store the unparsed date, and display it when we

also store the unparsed date, and display it when we
failed to parse a Date. This allows RFC-incompatible
dates to still be seen in e.g. read_body in their
original form, better than nothing. For safety split
any "<",">" out, something might rely on the date being
completely safe to print.

git-svn-id: https://svn.code.sf.net/p/squirrelmail/code/trunk/squirrelmail@12283 7612ce4b-ef26-0410-bec9-ea0150e637f0