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.

1988/rules

@@ -36,7 +36,7 @@ RULES:
 ---header items---
 name:    	Your name, of course!
 org:		School/Company/Organization
-email address:	Email address from a well known site
+email address: email address from a well known site
 postal address:	Postal address, include your country as well
 environment:	Indicate the Hardware & OS under which your program was tested
 entry:		A of B		<entry number such as 3 of 5, 1 of 1...>
@@ -84,9 +84,9 @@ X Newlines count as 1 character.  Assume a standard 8 character tab stop.
 			...!amdahl!obfuscate
 
 	   Amdahl talks to hplabs, decwrl, pyramid, sun, uunet, cbosgd, ...
-	   We will attempt to Email a confirmation of receipt of contest
-	   entries, however since Email is not reliable you may not receive it.
-	   People are strongly encouraged to submit entries via Email, however
+	   We will attempt to email a confirmation of receipt of contest
+	   entries, however since email is not reliable you may not receive it.
+	   People are strongly encouraged to submit entries via email, however
 	   one may mail entries the following postal address:
 
 		Landon Curt Noll
@@ -101,7 +101,7 @@ X Newlines count as 1 character.  Assume a standard 8 character tab stop.
 	  bottom left corner of the envelope.
 
 	7) Each person may submit up to 8 entries.  Multiple entries must
-	   be sent in separate Email letters or postal envelopes.
+	   be sent in separate emails or postal envelopes.
 
 
 ANNOUNCEMENT OF WINNERS: