Changes to mblaze.7

[larryhynes]

• Bump the date, due to -s/-S change in EXAMPLES
• Delete '^to ' in the list of tools
• Change 'write' to 'compose'
• Use 'Maildirs' for plural maildirs
• Remove 'related to'
• List MTAs and Maildir tools alphabetically
• big -> large
• big pile -> large corpus
• Change wording for EXAMPLES intro
• Change some wording in EXAMPLES
• Change 'msort -s' (by subject) to 'msort -S' (by size) in example

I've also added some space after each example - I think this makes them easier to 'scan' and parse.

[leahneukirchen]

Generally good, I'm not too fond of Maildirs, perhaps rather Maildir folders?

[larryhynes]

Done.