sending a sequence number with enter messages. screens use that
sequence number in clipboard grab and data messages. the server
uses the sequence number to order messages across clients. also
changed secondary screens to send clipboard updates on leaving
(or when grab occurs when not active) instead of on a query from
the server. primary effectively does the same. the query
message has been removed.
clipboard owner support (MS windows done, X windows partial)
added key transfer on ms windows
mutex fixes in CClient (had race conditions)
faster debug output in ms windows
changed temporary screen name to "secondary"
network fixes on ms windows (poll returned wrong result)
fixed transparent cursor on ms windows
