Updated comments.

  Renamed 'update_stats' to 'update_cache' too.
  Comment updates.
  Removed orphaned sorting method.

  This updates #72.
  New lua primitive: sort

  The sort value is unset, which means we default to showing
 messages in "oldest -> newst" order.

  Valid settings are currently:

      sort( "asc" | "desc" );

  This updates #72.
  If the sort() primtive is updated refresh messages.

  This ensures sorts are "instant".

  This updates #72.
  Updated the allowed sort types.

  Valid types are now one of:
    date-asc, date-desc, subject-asc, subject-desc, from-asc, from-desc.

  This updates #72.
  Comment/whitespace cleanup.
  Update the messages only when *setting* index-limit.

  This is a performance *AND* correctness fix :)
  Moved CMaildir::getFolders into CFile::get_all_maildirs.

  Clearly a function that gets all maildirs shouldn't be
 part of the maildir class - and I'm too lazy to create
 a maildir-collection class.
  Removed orphaned method declaration.
  Log the number of maildirs we find.

  This is to help with issue #76.
Fix maildir listing : include the root if it's a maildir
Merge branch 'master' of https://github.com/skx/lumail
add 'w' key in message mode for wrap/unwrap long lines.
fix tabs
Fix getch usage : it returns an int. Type variables accordingly