Change references of 'EMail' to '[Ee]mail'

Depending on if it was the beginning of the sentence the EMail would
become 'Email' or 'email'.

Some references of 'Email' were changed to 'email' as well as those were
not in the beginning of a sentence.

A few places some consistency of capitalised email address (made lower
case) were changed to match other places of the same pattern.

1991/rules

@@ -41,7 +41,7 @@ name:    	Your name, of course!
 
 org:		School/Company/Organization
 
-email address:	Email address from a well known site, or in a registered domain
+email address: email address from a well known site, or in a registered domain
 
 postal address:	Postal address
 		include your country as well
@@ -125,20 +125,20 @@ XThis last line is not terminated by a newline and ends in an EE
        in the public domain.  All copyrighted programs will be rejected.
 
     6) Entries must be received between 06-Mar-91 0:00 UTC and
-       16-May-91 0:00 UTC.  Email your entries the address found below.
-       (UTC is essentially equivalent to Greenwich Mean Time)
+       16-May-91 0:00 UTC (UTC is essentially equivalent to Greenwich Mean
+       Time). Email your entries to the address found below.
 
-       We will attempt to Email a confirmation of receipt of contest
-       entries, however since Email is not reliable you may not receive it.
+       We will attempt to email a confirmation of receipt of contest
+       entries, however since email is not reliable you may not receive it.
        We regret that we can no longer accept entries via postal mail.
 
-    7) Each person may submit up to 8 entries.  Only 1 entry per Email
-       letter.  If you submit multiple entries, be sure that each has a
-       unique entry number.
+    7) Each person may submit up to 8 entries.  Only 1 entry per email.
+       If you submit multiple entries, be sure that each has a unique
+       entry number.
 
        We will discard all but the latest email in the case of multiple
        entries with the same entry number.  Thus, if you wish to correct
-       a previously sent entry, re-send it with the same entry number.
+       a previously sent entry, resend it with the same entry number.
        Just to be sure email does not arrive out or sequence, note that 
        fact in the 'remark' item.