[patch] review requested: message-mode named pipes

[Luke Kenneth Casson Leighton]

http://bugs.winehq.org/attachment.cgi?id=19477

* functionality of non-message-mode (byte type) is preserved.

* putting too many messages into the queue runs wineserver out of file
descriptors, but the solutions to that are too much work for this
revision, to be included, so - tough.

* research indicates that message-mode is supposed to block when
resources are low, but that would require a per-file mutex.  again -
too much work for this revision.

l.